Boutsen left Williams and joined Ligier at the start of the season. His replacement was a returning Nigel Mansell, who had spent the previous two seasons driving for Scuderia Ferrari. Williams also recruited future 1996 world champion, Damon Hill, as one of their new test drivers. Williams failed to finish in the first Grand Prix of the season at Phoenix, both drivers retiring with gearbox problems. Patrese got back on track for the team in the next Grand Prix at Interlagos, coming second behind McLaren's Ayrton Senna. The 1991 San Marino Grand Prix saw both cars retiring again: Mansell after a collision and Patrese with an electrical failure after 17 laps. The Grand Prix at Monaco saw Mansell finish in a points-scoring position, coming second, 18 seconds behind Ayrton Senna. At the next race, the Canadian Grand Prix in Montreal, Williams locked out the front row only for Patrese to drop back with gearbox problems and Mansell to retire from the lead on the final lap with an electrical fault. At the following race, in Mexico, Williams achieved a 1–2, Patrese finishing ahead of Mansell to score 16 points for the Williams team. Williams then ran a streak of victories, with Mansell winning the French Grand Prix, five seconds ahead of Alain Prost's Ferrari. Mansell then won again at the British Grand Prix; it had been four years since a Briton had won the Grand Prix, Mansell having won it in 1987. Three consecutive victories became four when Mansell won again in Germany, with Patrese about 10 seconds behind him in second place. Senna ended Williams's run of victories by winning in Hungary, finishing five seconds ahead of Mansell. Mansell later won the Italian Grand Prix and the Spanish Grand Prix, while Patrese won the Portuguese Grand Prix after Mansell's race was ruined by a botched pitstop in which only three wheel nuts were fitted. Williams finished second in the Constructors' Championship, scoring 125 points in total, 14 points behind McLaren. Mansell finished second in the Drivers' Championship with 72 points, 24 points behind Senna.