Lewis Hamilton prepared to leave McLaren on a high by setting the fastest time in first practice for the season-ending Brazilian Grand Prix on Friday.
The Briton, who took his 2008 Formula One title at Interlagos and arrived in Brazil after winning the U.S. Grand Prix in Texas last Sunday, lapped the anti-clockwise layout with a best time of one minute 14.131 seconds in sunny but hazy conditions.
Red Bull's Sebastian Vettel, the championship leader who is favourite to clinch his third successive title on Sunday, was second fastest and just 0.009 off Hamilton's pace.
However the 25-year-old German set his time on this year's Pirelli tyres while Hamilton's came in a test of next year's prototype rubber.
Ferrari's Fernando Alonso, Vettel's only title rival but 13 points off the lead, was fifth on the timesheets and 0.261 slower than the quickest McLaren.
"The 2013-spec tyres here are a bit of a hybrid. It is the hard compound but the structure is different, the tyres weigh 1kg more," Pirelli motorsport head Paul Hembery told BBC television.
"It is a chance for the teams to gain some data because the cars are not adapted to this product. The information so far has been positive. The quickest times of the day have been on the prototype."
Australian Mark Webber and McLaren's Jenson Button were third and fourth with Alonso's Brazilian team mate Felipe Massa sixth.
Spaniard Alonso must finish on the podium on Sunday to have any hope of taking his third title while Vettel will be champion regardless of other results if he can secure fourth place or better.
Hamilton is moving to Mercedes next season, a team that has been largely uncompetitive this year with their only highlight Nico Rosberg's win in China.
The Briton acknowledged after arriving in Brazil that Sunday's race will be emotional, possibly also his last chance in a while to stand on top of the podium. He intends to go flat out to get there.
Michael Schumacher, the seven-times world champion who is retiring for the second time on Sunday, lapped 11th fastest for Mercedes.
The 43-year-old German had a special message for his fans on his helmet: "Life is about passions, thank you for sharing mine."