Spanish Renault driver Fernando Alonso set the fastest time in the free practice for Sunday's Brazilian Grand Prix.
The two-time world champion registered a time of 1 minute 12.314 seconds for the 4.309-kilometre circuit at Interlagos in the afternoon session on Friday.
The second-fastest time surprisingly belonged to Toro Roso's Sebastien Buemi.
In the morning session Mark Webber in a Red Bull was fastest in a time of 1:12.463, edging out the time set by Brazilian Red Bull driver Rubens Barrichello.
Championship leader Jenson Button posted the seventh-fastest time in the first session, but then managed to better that by registering the fifth-fastest time in the second session.
The only other driver apart from Button and Barrichello, who can still win the championship, Sebastian Vettel, had the third-fastest time in the morning, but then fell behind in the afternoon and had the seventh-fastest time.
The German Red Bull driver, who won the last race in Japan, told a German television station that he had received many suggestions how he could still win the title.
"I think the best suggestion is to simply not think too much and just drive as fast as I can to do as well as I can," he said.
Button leads teammate Barrichello by 15 points with Vettel a further two points adrift heading into the penultimate race of the season and only needs to finish third to be absolutely sure of the drivers' title.
Brawn need just one point to clinch the constructors' crown ahead of Red Bull.