with de Cesaris fourth, ahead of Piquet, Arnoux, Danner, Caffi and Moreno. Danner and Caffi both spun several times and had been lapped more than once, as had Moreno, who lost a front wheel and drove back to the pits on three wheels for a replacement. Caffi passed Danner for seventh on lap 50, and Moreno finally dropped out with differential failure after completing 57 laps. On lap 63, Patrese and Boutsen came up behind Piquet, who was lapping Danner's Rial. Boutsen took his chance and overtook his team-mate for second place before they lapped Danner. Patrese had been losing downforce and grip due to a loose diffuser on the rear of his car. By this time, only Senna and the two Williams cars were on the lead lap. Then on lap 67, with Senna comfortably ahead, the V10 Honda engine in his McLaren failed, and he pulled on to the infield just after the start-finish line to retire. Boutsen inherited the lead, and led the last three laps to beat his team-mate Patrese by just over thirty seconds. De Cesaris and Piquet, having unlapped themselves with Senna's retirement, finished third and fourth. Arnoux was fifth in the Ligier, with Caffi a further lap down in sixth, both Dallaras finishing in the points. Senna was classified seventh ahead of Danner eighth, the last surviving runner, three laps adrift. Boutsen later said, "I couldn't believe my eyes when I saw the 'P1' sign, and I drove very carefully for the rest of the race." It was Boutsen's first Grand Prix victory, and Patrese's third successive second-place finish. It was Dallara's first podium finish, and the only time both their cars finished in the points. It proved to be the last podium finish for de Cesaris, and the last points finish for Arnoux. It also proved to be Christian Danner's last race in Formula One, as he failed to qualify for any further Grands Prix before Rial left the sport at the end of the season. Race classification Championship standings after the race Drivers' Championship standings Constructors' Championship standings Note: Only the top five positions are included for both sets of standings. References Canadian Grand Prix Canadian Grand Prix Grand Prix Grand Prix