1991 Formula One World Championship

Alain Prost failed to win a race with Ferrari and was fired before the end of the season due to a dispute with the team.

Footwork Ford Four regulation changes were made to reduce aerodynamic efficiency and overall grip:[10][11] On the topic of safety, the FIA would perform more stringent testing of the survival cell, including seat belts, fuel tanks and rollbar.

At the start, Senna and Prost maintained their places while Mansell sliced ahead of Patrese and Piquet lost out to Alesi and Berger.

Patrese didn't last much longer, his gearbox failing and then the stationary car was hit by Roberto Moreno, forcing both of them out.

At the start, Patrese got ahead of Senna while Mansell had gearbox problems and retired after being hit by Martin Brundle's Brabham.

On the last lap, Eric van de Poele was set for a 5th-place finish but retired with a fuel pump problem.

On lap 43, Modena's engine blew in the tunnel and this blocked Patrese, who spun off into the wall and both were out, as ironically Alboreto well down in the Footwork had also retired with a blown Porsche engine in the Footwork leaving additional oil on the track at the Nouvelle chicane which later left Blundell's Brabham to spin off into the wall out of 10th place behind the leaders by lap 44 just after overtaking Bernard before he crashed.

At the Circuit Gilles Villeneuve in Montreal, the Williams cars were 1–2 in qualifying, Patrese on pole ahead of Mansell, Senna, Prost, Moreno and Berger.

On the last lap, Mansell waved to the crowd, and then he let his car's revs drop too low and stalled the Renault engine.

This left a delighted Piquet to take his last career win ahead of Modena, Patrese, de Cesaris, Bertrand Gachot and Mansell who was classified sixth.

The extremely bumpy Hermanos Rodriguez Autodrome in Mexico saw a number of incidents during practice, including Senna crashing at the very fast Peraltada while trying to take it a bit faster than usual and his car overturned when it hit the tire barrier.

Senna had come to Mexico City with a head injury that he got while jetskiing in Brazil, and had been critical of the dusty circuit's condition all through the weekend.

At the front, Patrese won with Mansell making it a Williams 1–2 ahead of Senna, de Cesaris, Moreno and Éric Bernard.

Therefore, Mansell won ahead of Berger, Prost, Senna (classified fourth for starting final lap), Piquet and Gachot.

At the halfway stage of the season, Senna led the Drivers' Championship with 51 points, with Mansell second with 33, Patrese third with 22, and Prost fourth with 21.

In the Constructors' Championship, McLaren led with 67 points, Williams close in second with 55, Ferrari third with 29, and Benetton fourth with 23.

The second half of the year started at the very fast forested Hockenheim circuit in Germany and Mansell continued where he left off, taking pole ahead of Senna, Berger, Patrese, Prost and Alesi.

No one, however could touch Mansell who won, with Patrese making it a Williams 1–2 ahead of Alesi, the recovering Berger, de Cesaris and Gachot.

At the popular and scenic Spa-Francorchamps circuit in Belgium, Senna took pole ahead of Patrese, Prost, Mansell, Berger, Alesi, Piquet and the new sensation, Schumacher.

Senna's engine then stopped for some time and because of that Piquet, Patrese and de Cesaris were right with him and allowing Alesi to remain in the lead.

There was controversy before the Italian Grand Prix at the Monza Autodrome near Milan as Schumacher signed a deal with Benetton which displeased Jordan who went to court.

The Estoril circuit near Lisbon hosted the Portuguese round, and Patrese took pole ahead of Berger, Senna, Mansell, Prost and Alesi.

As the Williams mechanic went to get a spare nut, the lollipop man, unaware of the trouble signalled for Mansell to depart.

Senna then let Berger through on lap 12 in order to hold up Mansell while Schumacher overtook Prost at the same time.

At the challenging Suzuka circuit in Japan, the McLarens took 1–2 in qualifying with Berger ahead of Senna, Mansell, Prost, Patrese and Alesi.

Senna let Berger pull away and then held up Mansell, who had to win to keep his World Championship hopes alive.

Berger won ahead of the successfully defending world champion Senna, Patrese, Prost, Martin Brundle and Modena.

At the start, in extremely torrential wet conditions, Patrese lost time and was quickly behind Piquet and Alesi had also got by him and Schumacher.

The conditions became better but after another seven laps, the weather started to become worse and more drivers began to spin off, including Mansell who smashed into a wall- which allowed McLaren to win the Constructors' Championship.

In the Constructors' Championship, McLaren-Honda was the World Champion with 139 points, with Williams-Renault second with 125, Ferrari third with 55.5, and Benetton-Ford fourth with 38.5.