Following his departure from McLaren, Prost quickly signed up for the Renault team ahead of the 1981 season. Unlike McLaren who had been having consistent problems over the past few years, Renault had been on the rise in and looked to be a serious championship contender for 1981. Since entering Formula One in 1977, Renault had been unique on the grid in being the only challenger with a turbo charged engine. In 1981 however, manufacturer rival Ferrari had developed their own turbo charger in retaliation to the ever improving Renault cars. Prost would be joined in the team by fellow Frenchman, René Arnoux. Arnoux would be competing in his third season with the team and like Prost was considered a star on the rise. A serious rivalry was expected over which Frenchman would be the fastest in France's premier grand prix team. The team would be on the back foot at the start of the championship, they would have to start the season with their 1980 chassis, the Renault RE20 for the opening races before their new car would be ready to make its track debut.
It was an underwhelming start to the season for the duo at the Long Beach Grand Prix. In qualifying, the two drivers struggled with grip as their Michelin tyres failed to match with the slippery street circuit. Prost came out on top in qualifying, fourteenth fastest in comparison to Arnoux's twentieth fastest time. His race lasted only a few hundred metres, caught in a midfield melee at the hairpin, Prost was rammed by his replacement at the McLaren team, Andrea de Cesaris and was out of the race on the first lap. Arnoux would complete the race, albeit several laps down on the leading cars. It was a troubling start to the season for the Renault team.
After their disaster in the United States, Renault showed signs of improvement in Brazil. Prost was fifth on the grid with Arnoux down in eighth, nonetheless they remained slower than the leading cars at Williams and Brabham. The wet conditions on Sunday provided a chance for the Renault's to close the gap but it would prove another difficult day for the team. At the first corner Prost was hit by Gilles Villeneuve's Ferrari dropping him to eighth. The same incident saw the cause for Arnoux to retire on the first lap. For much of the early stages, Prost was stuck behind the much slower Fittipaldi car of Keke Rosberg. After dispatching the Finn, Prost's race would end on the 20th lap when Didier Pironi lost control of his Ferrari and collided with the side of Prost's car. The first two races had yielded not a single point for the Renault team. Already their championship chances were questioned with Williams dominating the opening rounds.
Despite the team's opening drama, the third round in Argentina looked more promising. The team suddenly looked capable for a win. Prost had been threatening for pole position throughout the qualifying sessions, however he had to settle for second on the grid behind Nelson Piquet's Brabham. Nonetheless, Prost had managed to put his car ahead of the dominating Williams duo of Alan Jones and Carlos Reutemann. Arnoux meanwhile was in fifth position. At the start, Prost was to suffer from the infamous 'turbo lag'. In comparison to the atmospheric engines of the Ford-Cosworth's that the majority of the field was using, the turbos were more powerful however slower off the line. As a consequence, Prost dropped from second to fifth at the start. Ahead of him ran Piquet, Jones, Reutemann and Arnoux. A battle between Arnoux and Prost was denied when Arnoux hit a bird forcing him to drop behind Prost. Prost gained another position when Jones began to drop back with engine trouble. Prost was quick, however the leading cars of Piquet's Brabham and Reutemann's Williams were vastly superior in pace. Prost would thereafter drive a quiet race to secure his first podium at the same venue that had yielded him his first points on his grand prix debut a year before. Arnoux went on to finish in fifth position, an overall good performance for Renault which saw them secure some much needed points in the championship.
Three weeks later, the grand prix circus returned to Europe for the San Marino Grand Prix. Heading into the race, the paddock was surrounded in controversy about the use of flexible skirts used to enhance the ground effect concept. Notably, only Renault and the new Toleman team were found to be legal ahead of Friday practice. Until the illegal devices were removed, the Renault's and Toleman's were the only cars found on track in the morning practice session. The extra track time yielded a good qualifying, the two Renault's were third and fourth. Arnoux, for the first time outqualifying Prost as his teammate. Villeneuve's Ferrari took pole whilst Reutemann's Williams was in second. The race proved another disappointment, on the warm-up lap it was evident that Prost had gearbox issues. This meant at the start he quickly dropped right down into the mid-field. After only three laps, Prost had retired from the race when the problem became terminal. Arnoux, would finish the race outside the points due to his own reliability issues. The team's championship chances were in dire trouble, of the four races so far, the team had scored in only one of them.
For the Belgian Grand Prix at Zolder, the team finally were able to release their new car, the Renault RE30. With their slow start to the season, the team were in need of some strong results if they were to stay in reach of the championship. The RE30's debut did not go well, Arnoux failed to qualify due to a mechanical failure in qualifying whilst Prost struggled with handling problems and went only twelfth fastest. His race would last only two laps, Prost's clutch failing him shortly after the start. Renault's frustrating season continued.
After the disastrous debut of the RE30 in Belgium, Prost and Arnoux performed extensive testing of the new car in order to ensure its competitiveness ahead of the next round in Monaco. Heading into the race, the chassis had been much revised to improve both performance and reliability of the car. Nonetheless, the new Renault's were still struggling with handling issues, Prost was ninth whilst Arnoux was only thirteenth. Arnoux had damaged his RE30 in the warm-up and had to take the spare RE20 for the race. It was evident that the RE20 still had a performance advantage over the RE30, Arnoux had passed Prost in the early stages and was challenging for points before he crashed his car. Prost meanwhile was quietly driving in the lower half of the top ten before slowly ascending the field as more cars dropped out. He had climbed to sixth before on lap 42 his engine failed and he was forced to retire.
Following Monaco, the two Renault's went to Dijon for testing, Prost had a huge accident that saw him suffer a neck injury. His involvement in Spain was brought into question, however he arrived at the circuit ready to race albeit with a very sore neck. Despite the accident, the testing had payed off and Prost managed to put his RE30 fifth on the grid. Arnoux was still struggling and was only seventeenth. At the start, Prost maintained his fifth position. The early laps saw him dice with Mario Andretti's Alfa Romeo before disposing with the American and moving into fourth. He was then rewarded with third position when Alan Jones spun out. Towards the middle stages of the race, Prost was the fastest car on track and was quickly catching the leaders of Reutemann and Villeneuve ahead of him. Prost was seemingly having a chance for his first win when suddenly on lap 28 he veered off the circuit and into the barriers. It was a frustrating day, whilst pushing hard to catch the leaders, Prost had lost control of his car and was out of the race. With Arnoux finishing outside the points, Renault would once again leave with no points. After seven races the team had only managed to score once.
The mid-point of the season came at Prost, Arnoux and Renault's home grand prix, the French Grand Prix. It had been a disappointing season, despite regularly proving competitive, the Renault's had only scored in one grand prix this season. Testing had been extensive prior to the race in Dijon, it was critical for the team to perform well in front of their home crowd. The team knew the track better than anyone, Renault having performed countless testing miles on the circuit in the past. It was no surprise then to see the Renault's performing at their best during qualifying. Prost was a clear contender for pole position, however it was his French rival and teammate, Arnoux, who took the pole. Prost was then bumped down to third when his old teammate, John Watson, in the McLaren moved into second on the grid. It was an average start to the race for Renault, Arnoux dropped into the midfield whilst Piquet and De Cesaris stormed past Prost. Despite an average start, Prost's Renault remained competitive and he quickly disposed of the two McLaren's of De Cesaris and Watson ahead of him. Prost was now second to Piquet's Brabham who had already opened up an extensive lead. Whilst Prost was one of the quickest cars on track, Piquet remained untouchable. Behind him, Watson was all over his former teammates rear and was looking likely to pass. However on lap 59 the race was stopped, a heavy deluge of rain afflicted the circuit bringing out the red flag. The race was stopped and the cars lined back up on the grid waiting for the rain to dissipate. Prost had a chance of winning the race, however the Brabham of Piquet ahead of him had a significant pace advantage. With the recommendation of the head of Michelin, Pierre Dupasquier, Prost made a gamble to put on the ultra soft qualifying tyres in a move that would hopefully place him ahead of Piquet on the restart. Piquet who ran Goodyear tyres could not be assured of the durability of their tyres to replicate this move. On the restart, Prost got off the line perfectly and took the lead of the race. He was challenged in the opening laps by Watson behind him, however the McLaren threat would be removed when Watson slid wide into the gravel and lost position. Thereafter Prost remained unchallenged and took a dominant first win at his home grand prix. He finished a total of 31 seconds ahead of Watson in second position. Renault finally got success in 1981, a win at their home grand prix providing a perfect comeback. Arnoux, finished the race in fourth position pushing the team up to fourth in the constructors championship.
Despite the home win, Renault remained distanced for the fight for the lead of the constructor's championship. The team still had a strong chance for second in the championship, Ferrari and Brabham being the team's main competitors, however championship leaders, Williams were a further 33 points ahead of Renault in the championship. Prost's championship chances were also slim, his 13 points were significantly behind championship leader, Carlos Reutemann's 37. Nonetheless his chances were significantly better than Arnoux's whose chances were non existent with his meager 5 points. Nonetheless, the team had remained optimistic and they were expected to shine at Silverstone, the long fast straights would mean turbo teams like Renault and Ferrari were at a significant advantage. Renault had a strong chance of claiming a second victory in a row and had introduced a new rear wing for both Prost and Arnoux to better their chances. In qualifying the Renault's were untouchable, Arnoux often the faster qualfier took the pole position whilst Prost was alongside him in second place. Piquet was third whilst Ferrari seemed off the pace, Pironi only fourth whilst Villeneuve was in seventh: Prost got the best start of the two Renault's and immediately took the lead of the race. Arnoux dropped behind Pironi and Villeneuve, the two Ferrari's getting a strong start to the race. Prost immediately began opening up a lead whilst Arnoux was back in second. Pironi had dropped back, whilst Villeneuve had crashed out, taking Alan Jones out of the race with him. Within a few laps, two of the main championship contenders were out whilst Prost and Renault looked on course for a second successive victory. However after only 17 laps, Prost had retired. His engine whilst powerful remained unreliable and he suffered a serious loss in power before pulling into the pits to retire. Arnoux would lead the race, however he would be denied his first win of the season when he too would retire late in the race. The result was a serious blow for Renault's championship chances, in a race the team should have easily claimed a 1-2 finish, they would instead walk away with nothing. Prost dropped down to seventh in the championship standings whilst Renault had dropped down to sixth in the constructors standings.
Renault had wasted their victory chances at Silverstone, however the similar characteristics of the Hockenheim circuit for the German Grand Prix would give Renault another chance for victory. Renault had established in Britain that they were the fastest cars on the power circuits, their well-developed turbo engine providing a clear pace advantage, however as always it had proved unreliable. The Renault's once again dominated qualifying, however this time it was Prost on pole, not Arnoux. In the race, Arnoux dropped out immediately with a puncture, leaving Prost alone at the front. However his car did not prove as dominant as expected, the fast and nimble Williams cars of Reutemann and Jones were quickly closing in on his rear end. An exciting battle between Prost and Jones for the lead began to develop, Jones attacked hard but Prost proved equally resistant. Prost appeared to keep the Williams driver at bay, however on lap 21, Prost lost the lead to Jones when ironically he was blocked by his teammate, Arnoux whilst trying to lap him. Arnoux who had dropped well out of contention after his start line problems had inadvertently cost his team the race. Following being overtaken by Jones, Prost put his engine into low power mode, the team desperate to conserve the engine following its recent race problems. This decision would mean, Prost would be overtaken by Piquet's Brabham but it would allow him to finish the race and claim some much needed points for the team. Late in the race, Prost would be promoted back to second when Jones began to encounter mechanical problems. Prost would go on to finish the race in second place, behind Piquet. The team didn't win as expected but at least they had scored 6 points which allowed them to move back up into fifth in the championship.
Germany had proved to be the first conflict between Prost and Arnoux, Arnoux had potentially cost Prost a race win when he failed to let Prost past whilst he was being lapped. The move however was not deliberate and Prost had simply misjudged Arnoux's move to let him past, which subsequently allowed Jones to take the lead. Arnoux however was left frustrated at this stage of the season, he had rarely been able to shine, mechanical failure troubling him when he looked set to challenge Prost and he was sitting still on only 5 points compared to Prost's 19. The next round at the Osterreichring in Austria was another power circuit, Renault yet again would be able to exploit their power advantage. Arnoux took pole whilst Prost was right alongside him on the grid. Prost once again got the best start of the two Renault drivers, however Villeneuve's Ferrari took the lead when he stormed from third place. However it was not long before both Prost and Arnoux had moved past Villeneuve putting Renault back into a 1-2 position. Throughout the early stages of the race, Prost and Arnoux battled fiercly for the lead with Jacques Laffite's Ligier quickly coming up from third. A third opportunity in a row for a win was lost for Prost when he suffered a suspension failure on the 26th lap pitching him straight on at the first corner. Prost was out of the race whilst Arnoux failed to claim the win when Laffite moved past him, nonetheless Arnoux was finally able to get some points when he finished in second place. Arnoux's effort had meant the team had moved back into fourth place in the championship, only Williams, Brabham and Ligier remaining in front.
It had been a hard season for Prost, however only in his second season, he had finally began to feel content at Renault with their late season up-take in performance. The team was now regularly fighting for victories, even if their poor reliability had cost them a chance at the championship title. Prost was now heavily coverted driver in Formula One, many teams had been vying for his interest, including championship leading team, Williams. However Prost decided to remain faithful to Renault and believed their recent upswing of performance would mean they would be well positioned for the title in 1982, both Prost and Arnoux opted to re-sign for the team for the next season. The news also coincided with the birth of Prost's first son, Nicolas.
The Dutch Grand Prix at Zandvoort would prove to be another power circuit, typically this meant that Renault would be the fastest cars. Prost took pole on Saturday Qualifying after Arnoux had been fastest all day on Friday. In the race, Prost took an immediate lead whilst Arnoux quickly dropped down the field after making a wrong tyre call. Like in Germany, the Williams cars seemed set to challenge Renault and Alan Jones was quickly closing on the rear of Prost. As also in Germany, the two drivers were set for another big battle for the lead. Throughout the race, Jones attacked hard, however Prost remained calm and collected and kept the lead. After nearly a whole race of fighting Prost, Jones eventually could not keep up the charge and had began to destroy his tyres in his charge against Prost. Suffering from severe tyre degradation, Jones dropped way back and fell to third behind Piquet. This allowed Prost to take an easy second victory, the victory being the first time Renault were able to provide a result to their cars dominant potential. Arnoux suffered another retirement, however Prost's victory kept him in with a slim chance for the Drivers' Championship with three races to go. Reutemann lead the championship with 45 points whilst behind him sat Laffite on 34, Jones on 31 and Prost on 28. Prost remained among the final five drivers with a chance of the world crown.
Whilst Prost's championship chances remained slim, Renault remained committed to providing him with the best possible chance for taking the crown. For Monza, the team had provided upgrades to the RE30 aimed at improving air flow into the rear wing. Typically, both Prost and Arnoux were fastest during Friday qualifying. Arnoux would go on to take his fourth pole position of the season, however Prost was denied the chance to challenge his fastest time following a collision with Andrea de Cesaris during Saturday qualification. The delay in repairing his car had allowed Carlos Reutemann to snatch second position on the grid from him, meaning Prost would be forced to start from third. In the race, Prost made a terrific start to take the lead heading into the first corner. Arnoux would follow but would retire following an accident on the twelfth lap. This left Prost alone at the front, being left in a position to dominate the race. Prost seemed untouchable throughout the race and despite a late race charge by Alan Jones, Prost went on to take victory nine seconds ahead of his Williams championship rivals, Jones and Reutemann. The fourth championship challenger, Nelson Piquet finished in the last points place in sixth position. Prost had came out of Italy, the best of the five championship contenders, however his championship chances remained quite slim. He had overtaken Laffite in the standings and drawn level with Jones on 37 points, however ahead of him sat Piquet on 46 and Reutemann on 49.
The recent races, being situated on power circuits had well suited the powerful turbo engine of Renault, this had allowed Prost the opportunity to capitulise on the car's performance and bring him back in with a chance of winning the world title. However, the final two circuits at Montreal and Las Vegas were notably street circuits more suited to the more aero focussed, Williams, Ligier and Brabham cars. It would be much more of a challenge for Renault to be competitive on these circuits. Ahead of the Canadian Grand Prix at Montreal, Renault urgently brought further upgrades in an effort to match their rivals aerodynamic capability. In qualifying, Renault appeared to be performing at their best on a non-power circuit and Prost put his car fourth on the grid behind Piquet, Reutemann and Jones. Prost was able to pass Reutemann at the start and soon found he was challenging Piquet and Jones for the lead. The two leaders dropped back leaving Prost in the lead of the race. It looked good for yet another win for Prost, however he began to suffer from cold brakes, his car failing to get up to temperature in the cold Montreal conditions. Prost began to lose performance and with it a chance for victory. On lap 13, Laffite's Ligier took the lead whilst two laps later Prost collided with Villeneuve when the Ferrari driver moved to overtake. He would then further drop behind Watson's McLaren. Prost's race appeared to be in tatters, being unable to cope with his car in these conditions. He further dropped to fifth when the second Ferrari of Pironi overtook him. His race would come to an end on lap 45, when he collided with the back of the backmarker Lotus of Nigel Mansell. Both Prost and Mansell were out of the race, his failure to score in the penultimate round had meant that Prost's hopes of being World Champion in 1981 would come to an end.
For the final race in Las Vegas, Prost qualified his Renault in fifth place. This was markedly better than Arnoux who could only manage 13th on the grid. The start saw Prost move up to third where he sat behind Jones and Villeneuve. He battled hard with Villeneuve's Ferrari in the initial laps, before moving into second position on lap 3. Prost was competitive and began to quickly pull away from the rest of the field, he however could not catch Jones who appeared uncatchable in his final race before retirement. Prost however would begin to suffer from severe tyre degradation in the middle stages of the race, the hot conditions destroying his tyres. Forced to make a pit stop for a tyre change, Prost emerged from the pits in fifth position. His new tyres provided him with an extraordinary pace advantage and he soon disposed of Mansell, Piquet and Laffite ahead of him to move back into second position. Whilst Prost had fought to regain his second position, Jones had opened out a virtually uncatchable lead, forcing Prost to consolidate his second position. Prost went on to finish the final race of the season in second position, he had not managed to claim the title but Renault's late season return to form had set him up to be a formidable competitor in 1982.