The Williams began to improve at Monaco, where Mansell took second to Senna, and at the Canadian GP on 2 June it looked like Williams were finally ready to make their move. Mansell qualified 2nd, took the lead in the first corner, held it all the way and ended the penultimate lap with a commanding lead of more than a minute. Waving to the crowd, Mansell turned into the final hairpin, and the engine cut dead, the car coasting to a slow stop, a victim of electronic, “black box” gremlins. Few people remember that it was Nelson Piquet in a Benetton who came through to tale the checkered flag — for what would be his last F1 win.
The balance of the 1991 season would see a fruitless quest by Mansell and Williams to catch Senna, including a disqualification while leading at Estoril after a wheel fell off in the middle of the pit lane. Mansell won three in a row in France, England and Germany, and came into Suzuka needing two more victories (and no more than a 4th from Senna) to take the title. But he went off into the sand chasing the Brazilian on lap 10, and Aryton Senna had clinched his 3rd Formula One championship in four years. Classifications.
From the Races | F1A&G compilation.