Lewis Hamilton was fastest in the first day of practice for the season-ending Brazilian Grand Prix on Friday, while Formula One leader Sebastian Vettel was second and title challenger Fernando Alonso was fifth.
Hamilton, in his last race with McLaren, had a lap of 1 minute, 14.026 seconds in the second practice session at Interlagos, .274 quicker than Vettel's Red Bull. Vettel's teammate Mark Webber was third in 1:14.523.
Alonso clocked 1:14.592 in his afternoon run, just behind Ferrari teammate and home-crowd favorite Felipe Massa.
Vettel has a 13-point lead over Alonso and needs to finish fourth or better to become F1's youngest three-time champion at age 25.
He also can be the first to win three titles in a row since Michael Schumacher, who won five consecutive from 2000-2004. The only other driver with three straight championships is Juan Manuel Fangio, who lifted the trophy in consecutive seasons from 1954-1957.
Drivers from McLaren, Red Bull and Ferrari dominated the first session, but Mercedes improved in the second with Schumacher in sixth place and Nico Rosberg seventh.
Hamilton barely avoided a collision near the end of the first practice after a Marussia car spun in front of him.
Kimi Raikkonen ran wide at Turn 1 with his Lotus early in the second session, becoming the first driver to test the expanded runoff area added at the end of the main straight.
Kamui Kobayashi, preparing for probably his last race with Sauber after the team announced that 21-year-old Mexican Esteban Gutierrez would be Nico Hulkenberg's teammate next season, was 15th fastest in his second run.
HRT, possibly ending its spell in F1 because of financial difficulties, finished near the bottom of the timings with Pedro de la Rosa and Narain Karthikeyan.
Teams were given two sets of the prototype Pirelli tires that will be used next year, allowing them to get an idea of what to expect in their 2013 cars.
Drivers used the new tires during most of the morning session and part of the second, with Hamilton complaining of overheating at times. Sauber's Sergio Perez - who will be replacing the British driver at McLaren in 2013 - said the new sets had more mid-corner grip.
It was a hot and sunny day, but rain was expected for Saturday's qualifying and Sunday's race in Sao Paulo.
Red Bull has won the last three races in Brazil and Vettel finished second last year at Interlagos. The German driver has finished fourth or better in the last six races this year, and two-time champion Alonso hasn't won since the German GP in July.
In addition to crowning the champion, the Brazilian GP marks the end of Schumacher's career for the second time. F1's most successful driver, Schumacher retired with Ferrari in 2006 and returned with Mercedes in 2010. But he's managed nothing more than a podium finish this year.
It will be the sixth time since 2005 that the F1 season will be decided at the Brazilian GP. Alonso won both of his titles at Interlagos in 2005 and '06.
