The 1991 San Marino Grand Prix was a Formula One motor race held at Imola on 28 April 1991. It was the third race of the 1991 Formula One World Championship.

The 61-lap race was won by Brazilian Ayrton Senna, driving a McLaren-Honda, after he started from pole position. His Austrian teammate Gerhard Berger finished second, with Finn JJ Lehto third in a Dallara-Judd. It was also McLaren's first 1-2 finish since the 1989 Belgian Grand Prix. This was Senna's final win at the San Marino Grand Prix before his death in 1994.

Pre-race With the team under new management having been sold by Cyril De Rouvre, Stefan Johansson was replaced at AGS by Formula One debutant Fabrizio Barbazza.

Qualifying Pre-qualifying report In the pre-qualifying session on Friday morning, Andrea de Cesaris was fastest in the Jordan, just under four tenths of a second faster than JJ Lehto's Dallara in second. De Cesaris' team-mate Bertrand Gachot was third, just a few hundredths behind Lehto. The fourth pre-qualifier was Eric van de Poele in the Lambo, who edged out the second Dallara of Emanuele Pirro. It was van de Poele's first progression through to the main qualifying sessions, and the first time in 1991 that a Dallara had failed to pre-qualify.

Apart from Pirro, those who failed to pre-qualify included Olivier Grouillard in the new British-built Fomet-1 chassis debuted by the Fondmetal team. Despite teething troubles which prevented him from progressing any further, Grouillard said he was happy with the new car. Seventh was the other Lambo of Nicola Larini, and bottom of the time sheets was Pedro Chaves in the sole Coloni, who suffered a gearbox failure during the session.

Pre-qualifying classification Pos No Driver Constructor Time Gap 1 33 Andrea de Cesaris Jordan-Ford 1:25.535 — 2 22 JJ Lehto Dallara-Judd 1:25.923 +0.388 3 32 Bertrand Gachot Jordan-Ford 1:25.980 +0.445 4 35 Eric van de Poele Lambo-Lamborghini 1:26.117 +0.582 5 21 Emanuele Pirro Dallara-Judd 1:26.305 +0.770 6 14 Olivier Grouillard Fondmetal-Ford 1:26.789 +1.254 7 34 Nicola Larini Lambo-Lamborghini 1:26.886 +1.351 8 31 Pedro Chaves Coloni-Ford 1:31.239 +5.704

Qualifying report Ayrton Senna claimed his 55th pole position from Riccardo Patrese, Alain Prost, Nigel Mansell and Gerhard Berger.

Qualifying classification Pos No Driver Constructor Q1 Q2 Gap11 Ayrton SennaMcLaren-Honda1:21.8771:43.633 —26 Riccardo PatreseWilliams-Renault1:21.9571:42.455 +0.080327 Alain ProstFerrari1:22.1951:42.429 +0.31845 Nigel MansellWilliams-Renault1:22.3661:41.878 +0.48952 Gerhard BergerMcLaren-Honda1:22.5671:40.322 +0.69064 Stefano ModenaTyrrell-Honda1:23.5111:44.613 +1.634728 Jean AlesiFerrari1:23.9451:41.149 +2.068824 Gianni MorbidelliMinardi-Ferrari1:24.762no time +2.885923 Pierluigi MartiniMinardi-Ferrari1:24.807no time +2.930103 Satoru NakajimaTyrrell-Honda1:25.3451:42.063 +3.4681133 Andrea de CesarisJordan-Ford1:25.4911:44.118 +3.6141232 Bertrand GachotJordan-Ford1:25.5311:44.897 +3.6541319 Roberto MorenoBenetton-Ford1:25.6551:45.216 +3.7781420 Nelson PiquetBenetton-Ford1:25.8091:42.911 +3.9321515 Maurício GugelminLeyton House-Ilmor1:25.841no time +3.9641622 JJ LehtoDallara-Judd1:25.9741:43.397 +4.0971729 Éric BernardLola-Ford1:25.983no time +4.106187 Martin BrundleBrabham-Yamaha1:26.055no time +4.1781926 Érik ComasLigier-Lamborghini1:26.2071:46.667 +4.3302030 Aguri SuzukiLola-Ford1:26.356no time +4.4792135 Eric van de PoeleLambo-Lamborghini1:26.5501:47.619 +4.6732216 Ivan CapelliLeyton House-Ilmor1:26.6021:52.949 +4.725238 Mark BlundellBrabham-Yamaha1:26.7781:49.539 +4.9012425 Thierry BoutsenLigier-Lamborghini1:26.9981:44.125 +5.1212511 Mika HäkkinenLotus-Judd1:27.3241:47.444 +5.4472612 Julian BaileyLotus-Judd1:27.9761:45.931 +6.0992717 Gabriele TarquiniAGS-Ford1:28.175no time +6.2982818 Fabrizio BarbazzaAGS-Ford1:29.665no time +7.7882910 Alex CaffiFootwork-Porsche1:30.2802:06.589 +8.403309 Michele AlboretoFootwork-Porsche 1:30.76219:39.741 +8.885

Race Race report The formation lap saw two dramatic incidents: Prost spun off the track at Rivazza Turn, followed by Berger, who was able to continue. However Prost stalled the engine and did not take the start.

At the lights, Patrese took the lead ahead of Senna, whilst Mansell, already slow off the line with gearbox problems, retired near the end of lap 1 after a collision with Martin Brundle. He was followed out by Nelson Piquet who spun off on lap 2, Aguri Suzuki who spun off on lap 3 behind the leaders and Jean Alesi who also spun off on lap 3 attempting a rather foolhardy pass on Stefano Modena.

In a strong lead, Patrese pitted for originally what appeared to be an early stop to slicks turned out to be more serious – a misfire with a faulty camshaft sensor. He restarted last before retiring for good 9 laps later.

Berger was catching Senna, lapping 1.5 seconds quicker than his teammate. The lead was soon down to 5 seconds, with Modena a superb third from Satoru Nakajima and the two Minardis of Pierluigi Martini and Gianni Morbidelli.

Both McLarens pitted for tyres with Senna maintaining his lead. Just after setting fastest lap, Berger was delayed in traffic, held up by the trio of Maurício Gugelmin, Julian Bailey and Thierry Boutsen. Bailey himself moved past Andrea de Cesaris into 6th, whilst Nakajima retired with transmission problems.

Ivan Capelli spun into retirement from fourth to hand over to JJ Lehto's Dallara. Modena retired with transmission problems which meant that behind the two dominant McLarens, the order was now Roberto Moreno, Lehto, Eric van de Poele for the little Modena team and Martini's Minardi. Meanwhile, de Cesaris eventually retired in the pits with gearbox problems on lap 38.

Moreno's gearbox broke on lap 52 causing him to retire, whilst Senna was having problems with oil pressure caused by the special high-torque Honda V12. As the Leyton House of Maurício Gugelmin eventually retired with an engine failure on lap 58. Berger put in a series of fastest laps to cut Senna's lead to just 1.7s at the line. Eric van de Poele had retired on the last lap as the result of fuel pump problems.

Lehto was overjoyed to gain the first and only podium place of his career for Dallara, with Martini fourth. Van de Poele's drive ended when a fuel pump broke on the last lap – he was classified ninth overall. The Lotus drivers of Mika Häkkinen and Bailey took fifth and sixth, both scoring their first world championship points, an unexpected result for the troubled team since their cars had barely managed to get on to the grid with Häkkinen 25th and Bailey 26th. This race was also noted for being the only Formula One point for Julian Bailey.

Race classification Pos No Driver Constructor Laps Time/Retired Grid Points 1 1 Ayrton Senna McLaren-Honda 61 1:35:14.750 1 10 2 2 Gerhard Berger McLaren-Honda 61 + 1.675 5 6 3 22 JJ Lehto Dallara-Judd 60 + 1 lap 16 4 4 23 Pierluigi Martini Minardi-Ferrari 59 + 2 laps 9 3 5 11 Mika Häkkinen Lotus-Judd 58 + 3 laps 25 2 6 12 Julian Bailey Lotus-Judd 58 + 3 laps 26 1 7 25 Thierry Boutsen Ligier-Lamborghini 58 + 3 laps 24 8 8 Mark Blundell Brabham-Yamaha 58 + 3 laps 23 9 35 Eric van de Poele Lambo-Lamborghini 57 Fuel pump 21 10 26 Érik Comas Ligier-Lamborghini 57 + 4 laps 19 11 7 Martin Brundle Brabham-Yamaha 57 + 4 laps 18 12 15 Maurício Gugelmin Leyton House-Ilmor 55 Engine 15 13 19 Roberto Moreno Benetton-Ford 54 Gearbox 13 4 Stefano Modena Tyrrell-Honda 41 Transmission 6 33 Andrea de Cesaris Jordan-Ford 37 Gearbox 11 32 Bertrand Gachot Jordan-Ford 37 Suspension 12 16 Ivan Capelli Leyton House-Ilmor 24 Spun off 22 29 Éric Bernard Lola-Ford 17 Engine 17 6 Riccardo Patrese Williams-Renault 17 Electrical misfire 2 3 Satoru Nakajima Tyrrell-Honda 15 Transmission 10 24 Gianni Morbidelli Minardi-Ferrari 10 Gearbox 8 28 Jean Alesi Ferrari 2 Spun off 7 30 Aguri Suzuki Lola-Ford 2 Spun off 20 20 Nelson Piquet Benetton-Ford 1 Spun off 14 5 Nigel Mansell Williams-Renault 0 Collision 4 27 Alain Prost Ferrari 0 Spun off 3 17 Gabriele Tarquini AGS-Ford 18 Fabrizio Barbazza AGS-Ford 10 Alex Caffi Footwork-Porsche 9 Michele Alboreto Footwork-Porsche 21 Emanuele Pirro Dallara-Judd 14 Olivier Grouillard Fondmetal-Ford 34 Nicola Larini Lambo-Lamborghini 31 Pedro Chaves Coloni-Ford

Championship standings after the race

Drivers' Championship standings PosDriverPoints 1 Ayrton Senna 30 3 2 Gerhard Berger 10 1 3 Alain Prost 9 1 4 Riccardo Patrese 6 1 5 Nelson Piquet 6Source:

Constructors' Championship standings Pos Constructor Points 1 McLaren-Honda 40 2 Ferrari 10 3 Williams-Renault 6 4 Benetton-Ford 6 5 Tyrrell-Honda 5Source:

References