Keke Rosberg's fifth and final Grand Prix victory came at the 1985 Australian Grand Prix on the brand new Adelaide Street Circuit. As it was the final race of the season, it was also Rosberg's final race for Williams. Keke gave the winners trophy to his race engineer, Frank Dernie. The win enhanced Rosberg's reputation as a "street fighter" as four of his five championship Grand Prix wins (Monaco, Dallas, Detroit and Adelaide) had all come on street circuits. Rosberg handled the 35°C heat better than most and won by 43 seconds from the Ligier Renaults of Jacques Laffite and Philippe Streiff.