The 1981 San Marino Grand Prix was a Formula One motor race held at Imola on 3 May 1981. It was the fourth race of the 1981 Formula One World Championship.

The race was the first to bear the title "San Marino Grand Prix", although the Imola circuit is in Italy and several non-championship Formula One races and the 1980 Italian Grand Prix had previously been held at the circuit. The Acque-Minerali chicane had been widened from the year before and was faster; the chicane in its original narrow configuration in 1980 was unpopular with drivers because it was very slow.

The Lotus team withdrew their entries because the FIA upheld the ban on the Lotus 88 and team owner Colin Chapman felt the 81s were no longer competitive.

Gilles Villeneuve took the early lead until an ill-fated pit stop for slick tyres, whereafter Didier Pironi held the lead until late in the race and was passed by Nelson Piquet, who eventually won the race. As well as being Michele Alboreto's Grand Prix debut, the race is also notable for the recovery of Gilles Villeneuve to seventh place, after misjudgement of tyre selection for the conditions. While the team did not qualify for the race, it was the first race entered by Toleman, which is now Alpine F1 Team.

Classification Qualifying Pos No Driver Constructor Q1 Q2 Gap 1 27 Gilles Villeneuve Ferrari 1:35.576 1:34.523 — 2 2 Carlos Reutemann Williams-Ford 1:35.844 1:35.229 +0.706 3 16 René Arnoux Renault 1:35.281 1:35.292 +0.758 4 15 Alain Prost Renault 1:35.579 3:58.089 +1.056 5 5 Nelson Piquet Brabham-Ford 1:37.417 1:35.733 +1.210 6 28 Didier Pironi Ferrari 1:36.168 1:35.868 +1.345 7 7 John Watson McLaren-Ford 1:37.639 1:36.241 +1.718 8 1 Alan Jones Williams-Ford 1:36.280 1:36.317 +1.757 9 29 Riccardo Patrese Arrows-Ford 1:37.061 1:36.390 +1.867 10 26 Jacques Laffite Ligier-Matra 1:38.908 1:36.477 +1.954 11 23 Bruno Giacomelli Alfa Romeo 1:39.372 1:36.776 +2.253 12 22 Mario Andretti Alfa Romeo 1:37.587 1:36.919 +2.396 13 6 Héctor Rebaque Brabham-Ford 1:38.822 1:37.264 +2.741 14 8 Andrea de Cesaris McLaren-Ford 1:38.019 1:37.382 +2.859 15 20 Keke Rosberg Fittipaldi-Ford 1:37.459 1:37.906 +2.936 16 33 Patrick Tambay Theodore-Ford 1:39.215 1:37.545 +3.022 17 4 Michele Alboreto Tyrrell-Ford 1:39.341 1:37.771 +3.248 18 25 Jean-Pierre Jabouille Ligier-Matra 1:38.140 1:38.702 +3.617 19 3 Eddie Cheever Tyrrell-Ford 1:38.369 1:38.266 +3.743 20 32 Beppe Gabbiani Osella-Ford 1:39.245 1:38.302 +3.779 21 14    Marc Surer Ensign-Ford 1:38.341 1:38.488 +3.818 22 31 Miguel Angel Guerra Osella-Ford 1:39.799 1:38.773 +4.250 23 18 Eliseo Salazar March-Ford 1:39.161 1:38.827 +4.304 24 10 Slim Borgudd ATS-Ford 1:41.196 1:39.079 +4.556 25 30 Siegfried Stohr Arrows-Ford 1:39.112 1:39.553 +4.589 26 17 Derek Daly March-Ford 1:39.453 1:39.157 +4.634 27 9 Jan Lammers ATS-Ford 1:40.872 1:39.419 +4.896 28 21 Chico Serra Fittipaldi-Ford 1:51.453 1:41.114 +6.591 29 36 Derek Warwick Toleman-Hart 1:54.020 1:43.187 +8.664 30 35 Brian Henton Toleman-Hart 1:49.951 no time +15.428 11 Elio de Angelis Lotus-Ford — — — 12 Nigel Mansell Lotus-Ford — — —

Race Pos No Driver Constructor Tyre Laps Time/Retired Grid Points 1 5 Nelson Piquet Brabham-Ford 60 1:51:23.97 5 9 2 29 Riccardo Patrese Arrows-Ford 60 + 4.58 9 6 3 2 Carlos Reutemann Williams-Ford 60 + 6.34 2 4 4 6 Héctor Rebaque Brabham-Ford 60 + 22.89 13 3 5 28 Didier Pironi Ferrari 60 + 25.87 6 2 6 8 Andrea de Cesaris McLaren-Ford 60 + 1:06.61 14 1 7 27 Gilles Villeneuve Ferrari 60 + 1:41.97 1   8 16 René Arnoux Renault 59 + 1 Lap 3   9 14    Marc Surer Ensign-Ford 59 + 1 Lap 21   10 7 John Watson McLaren-Ford 58 + 2 Laps 7   11 33 Patrick Tambay Theodore-Ford 58 + 2 Laps 16   12 1 Alan Jones Williams-Ford 58 + 2 Laps 8   13 10 Slim Borgudd ATS-Ford 57 +3 Laps 24   25 Jean-Pierre Jabouille Ligier-Matra 45 Not Classified 18   17 Eliseo Salazar March-Ford 38 Spun Off 23   4 Michele Alboreto Tyrrell-Ford 31 Collision 17   32 Beppe Gabbiani Osella-Ford 31 Collision 20   23 Bruno Giacomelli Alfa Romeo 28 Collision 11   3 Eddie Cheever Tyrrell-Ford 28 Collision 19   22 Mario Andretti Alfa Romeo 26 Gearbox 12   20 Keke Rosberg Fittipaldi-Ford 14 Engine 15   26 Jacques Laffite Ligier-Matra 7 Suspension 10   15 Alain Prost Renault 3 Gearbox 4   31 Miguel Angel Guerra Osella-Ford 0 Accident 22   30 Siegfried Stohr Arrows-Ford     18 Derek Daly March-Ford     9 Jan Lammers ATS-Ford     21 Chico Serra Fittipaldi-Ford     36 Derek Warwick Toleman-Hart     35 Brian Henton Toleman-Hart     11 Elio de Angelis Lotus-Ford     12 Nigel Mansell Lotus-Ford        

Notes

This was the Formula One World Championship debut for Swedish driver Slim Borgudd, British driver Derek Warwick and Italian driver and future Grand Prix winner Michele Alboreto. This was the 250th Grand Prix in which an Australian driver participated. Only British, American, French and Italian drivers had participated in more Formula One World Championship Grands Prix. This race marked the 50th podium finish for a Brazilian driver. This was the Formula One World Championship debut for British constructor Toleman. It was also the 5th Grand Prix start for Theodore and the 50th Grand Prix start for Renault and a Renault-powered engine. This race marked the 25th Grand Prix win for Brabham. This was the Formula One World Championship debut for British engine supplier Hart.

Championship standings after the race

Drivers' Championship standings Pos Driver Points 1 Carlos Reutemann 25 2 Nelson Piquet 22 3 Alan Jones 18 4 Riccardo Patrese 10 5 Alain Prost 4Source:

Constructors' Championship standings Pos Constructor Points 1 Williams-Ford 43 2 Brabham-Ford 25 3 Arrows-Ford 10 4 Renault 6 5 Alfa Romeo 3Source:

Note: Only the top five positions are included for both sets of standings.

References