Ghinzani announced his decision to retire from Grand Prix racing before official practice of the final race of the 1989 season in Australia. He qualified 21st for his final race, but it ended when his Osella was violently hit from behind by the Lotus of triple World Champion Nelson Piquet on lap 19 under braking for the hairpin at the end of the fast Brabham Straight. Piquet, whose helmet was hit by one of the Osella's rear wheels but who was not hurt, stated that he simply had not seen Ghinzani until he hit him due to the amount of spray. During the race, 1989 World Champion Alain Prost refused to drive more than one lap in protest of the dangerous conditions caused by persistent and heavy rain.