During the 1980s and early 1990s Prost formed a fierce sporting rivalry, mainly with Ayrton Senna but also Nelson Piquet and Nigel Mansell. In 1986, at Adelaide in the last race of the season, he beat Mansell and Piquet of Williams to the title, after Mansell retired late in the race and Piquet was pulled in for a late precautionary pit stop. Senna joined Prost at McLaren in 1988 and the two had a series of controversial clashes, including a collision at the 1989 Japanese Grand Prix that gave Prost his third Drivers' Championship. A year later at the same venue they collided again, but this time Prost, driving for Ferrari, lost out. Before the end of a winless 1991 season Prost was fired by Ferrari for his public criticism of the team. After a sabbatical in 1992, he joined the Williams team, prompting Mansell, the reigning Drivers' Champion, to leave for CART. With a competitive car, Prost won the 1993 championship and retired from Formula One driving at the end of the year.