McLaren set the pace in Friday's Brazilian Grand Prix practice with Colombian Juan Pablo Montoya the fastest race driver.
Renault's Fernando Alonso, who can become Formula One's youngest champion on Sunday, had lapped quicker than McLaren's Kimi Raikkonen in the first hour-long session although times mean little on a Friday.
However, the Finn was faster than the 24-year-old Spaniard in the afternoon.
Alonso leads Raikkonen by 25 points and need only finish third to secure the title with two races to spare. Renault are six points ahead of McLaren, who have won the last four races, in the constructors' standings.
"It was a bit confusing today, really," said Alonso. "We were quick in the first session and then this afternoon there were quite a lot of people in front of us.
"Overall, I still have lots of confidence for the rest of the weekend and I am sure we can be quick."
Austrian test driver Alexander Wurz showed off McLaren's speed at the anti-clockwise Interlagos track with the best time in both sessions -- his fastest of one minute 11.701 seconds coming in the morning.
Wurz will not race on Sunday, while Montoya's only hope of repeating his win in Brazil last year will be if there is no chance of Raikkonen winning the drivers' championship. Otherwise, he will let the Finn past.
ANGRY SATO
Japan's Takuma Sato, angry and upset after being told this week that Honda-backed BAR will drop him at the end of the season, clocked the second best time of the morning.
Red Bull's Christian Klien provided the only real incident of the afternoon when he spun backwards into the tyre wall at the Bico de Paco corner. The Austrian walked away unhurt.
While Sunday's race was shaping up to be another battle between the top two teams, with BAR showing signs of mounting a challenge as well, Ferrari again looked some way off the frontrunners.
Seven times world champion Michael Schumacher was 12th and eighth in the two sessions.
Brazilian team mate Rubens Barrichello, hoping for a strong performance in his last home race for Ferrari, managed the fifth best time in the afternoon.
"We had no major problems although the car was a bit difficult over the bumps to begin with," said Ferrari technical director Ross Brawn. "The engineers made a few changes to overcome that."
Barrichello has a terrible record at Interlagos, retiring for nine years in a row before last year's third place, but was still keeping his hopes up.
"There are chances and I just take them," he had said.
"With the knowledge that I have in Brazil, with the last two pole positions that I had, with the public behind me, I'm going to give everything because for me it would mean a lot to win my home grand prix with Ferrari."
