Turbo engines were banned from 1989, and McLaren-Honda were the strongest team once again: Ayrton Senna won six races and started from pole 13 times, while Alain Prost won four but retired less often.
Relations between the team-mates turned sour. At the Japanese Grand Prix Senna went for a move on Prost at the chicane and the cars collided; Senna rejoined and crossed the line first, but he was disqualified, and Prost became champion for the third time. The race went to Alessandro Nannini in a Benetton.