Red Bull's title challenger Sebastian Vettel was quickest in second free practice for Sunday's Singapore Grand Prix.
Vettel has a distant chance of claiming the title, trailing leader Jenson Button by 26 points with 40 available for the rest of the season.
Renault driver Fernando Alonso put in a scorching lap late on to go second, in Renault's first race since Flavio Briatore and Pat Symonds left the team after the race-fix scandal.
Button was fifth fastest in his Brawn, with team mate and closest title rival Rubens Barrichello in 11th.
The only other driver with a chance of the title Mark Webber was sixth fastest, despite the fact he had to sit out the second half of the session after spinning his Red Bull at the first corner. The session was held up as a result of his off.
In the earlier session, Barrichello had set the pace but the session was also held up after an off by Renault's Romain Grosjean. His spin was at turn 17, the same corner where Renault asked Nelson Piquet Jr to deliberately crash at last year.