Sao Paulo  - Mark Webber in a Red Bull was fastest in the first free practice session Friday for the Brazilian Grand Prix.

The Australian registered a time of 1 minute 12.463 seconds for the 4.309-kilometre circuit at Interlagos, 0.411 seconds faster than Brawn GP's Rubens Barrichello.

Sebastian Vettel of Red Bull was third fastest with championship leader Jenson Button seventh in the second Brawn.

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.(dpa)