Jenson Button ensured that McLaren remained top in Brazil after topping the practice in the final practice session at Interlagos.
Team-mate Lewis Hamilton had led the way in both Friday sessions but it was Button's turn to top the times in Saturday morning's running as he edged out the Red Bull of Sebastian Vettel to spot.
The Briton set a best time of 1min 13.188secs to beat Vettel by just 0.057secs as the German again had the legs over title rival Fernando Alonso – with the Ferrari man only able to end up eighth quickest after being forced to abandon his final run
Vettel had however looked like ending the session in the lower reaches of the top ten – only vaulting up to second spot with his final run.
Behind the top two, Mark Webber was third fastest in the second Red Bull, two tenths of a second down on Button's benchmark and only a fraction ahead of Hamilton in he second McLaren.
The Lotus of Romain Grosjean and Paul di Resta's Force India then completed the top six.
Nico Hulkenberg, who took pole on his last appearance in Sao Paulo was seventh ahead of Alonso, Pastor Maldonado and Felipe Massa.
At the back in the race for tenth in the constructors' championship, Caterham pair Vitaly Petrov and Heikki Kovalainen ended up ahead of Marussia duo Timo Glock and Charles Pic.
The session didn't pass without some troubles however, with Kimi Raikkonen unable to set a time after the Renault engine in the back of his Lotus let go at the start of what would have been his first flying lap – leaving the Enstone-based team with work to do to fit a replacement in time for qualifying.
Bruno Senna also suffered a spin in his Williams, with Michael Schumacher forced to take avoiding action in his Mercedes to avoid the Brazilian.