McLaren's Jenson Button took advantage of dry conditions to top the times in Saturday's final practice session for the Korean Grand Prix.
The 2009 world champion flew round the Korean International Circuit in Yeongam in a time of one minute 36.910 seconds during his final lap of the session.
His McLaren teammate and fellow Briton Lewis Hamilton, world champion in 2008, had set the pace for the majority of the session but ran wide on his final lap and wound up second fastest and almost 0.3 seconds slower.
Red Bull's Australian driver Mark Webber was third fastest ahead of Ferrari drivers Fernando Alonso of Spain and Brazil's Felipe Massa.
Veteran German Michael Schumacher finished the session sixth quickest for Mercedes followed by Renault driver Vitaly Petrov of Russia and German Adrian Sutil of Force India.
Newly-crowned double champion Sebastian Vettel of Red Bull finished the session ninth quickest after being held up by Toro Rosso driver Spaniard Jaime Alguesuari during his final flying laps.
German Nico Rosberg was tenth fastest for Mercedes.