BRAZILIAN GRAND PRIX
Venue: Interlagos Dates: 16-18 October 2009 Coverage: Comprehensive live coverage of Friday practice, Saturday qualifying and Sunday's race - which starts at 1700 BST - across BBC TV, radio and online platforms.
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Fernando Alonso set the pace with a lap time of one minute 12.314 at Interlagos
Renault's Fernando Alonso topped the timesheets in second practice for the Brazilian Grand Prix as all three title hopefuls finished in the top seven.
Rubens Barrichello was third fastest for Brawn GP, 0.145 seconds off the pace while championship leader Jenson Button set the fifth fastest time.
Red Bull's title-chasing German driver Sebastian Vettel was seventh quickest.
Toro Rosso's Sebastien Buemi was an impressive second with Red Bull's Mark Webber splitting the Brawns in fourth.
Button will win the world championship if he gets a podium finish in Brazil and the Englishman can also triumph if his two title rivals, Barrichello and Vettel, fail to score heavily.
"I think it needs a problem for either Rubens or Vettel to catch him, said Brawn team boss Ross Brawn.
"I must admit, I was impressed with Jenson today. He worked well on the car, and he was quick and consistent.
"I have to admit we struggled with our nemesis, tyre temperature a little bit, but we are expecting it to be warmer tomorrow. The car looks pretty competitive this weekend."
WORLD TITLE RACE IN A NUTSHELL
Button will win the title in Brazil if...
He finishes third or better
OR He finishes fourth and Barrichello does not win
OR Vettel finishes lower than second and Barrichello finishes lower than fourth
OR He loses no more than four points to Barrichello
The F1 points system is: 1st - 10pts; 2nd - 8pts; 3rd - 6pts; 4th - 5pts; 5th - 4pts; 6th - 3pts; 7th - 2pts; 8th - 1pts
Ferrari-bound Alonso set the day's fastest lap late on with an impressive effort of one minute 12.314 secs, which was quicker than Felipe Massa's 2008 pole lap for the Prancing Horse.
The Red Bull pair of Vettel and Webber set the early pace with McLaren's Heikki Kovalainen enjoying a brief cameo appearance at the top of the timesheets.
Buemi then led the way until Button snatched top spot after 25 minutes, and the world champion elect then promptly improved upon his own time.
"The car seems to be working well on the prime tyre which is encouraging and the pace was good," said Button.
"I am struggling a little with the balance on the option tyre over one timed lap so hopefully we can resolve that overnight to be ready for qualifying."
By contrast Button's team-mate preferred the softer tyre.
"The car felt better when we put the softer option tyre on towards the end of the day and I was able to put in a good lap," said Barrichello.
"It is great to finally get the track action underway today," continued the Brazilian.
"I am pleased with our progress and happy to be starting my home grand prix weekend at the top end of the field."
Not be outdone, Buemi responded quickly to Button's challenge by posting a lap that was 0.011 secs inside the Englishman's effort, and then proceeded to shave almost two-tenths off his own hot lap.
The 20-year-old Swiss driver then held onto top spot for almost an hour before Alonso stole his thunder right at the death.
"I am happy that we seemed quite competitive in the afternoon," said Buemi after the session.
"I think we showed good speed, even though this is my first time driving at this circuit. Now we have a solid basis on which to improve tomorrow.
"Today's session shows that our pace in Japan [where Buemi was in the top six in all three practice sessions] was not just a one-off. So, I am quite confident for the rest of the weekend."
Rain had earlier halted proceedings in Friday's morning session at Interlagos but although the second session was run under gloomy skies it was not overly-affected by rain. However there were spots of drizzle in Sao Paulo and the officials designated it a wet session with 26 minutes remaining.
Less than a second separated the entire field as we got a fascinating glimpse of how competitive Sunday's grand prix could be as different sectors of the undulating Interlagos circuit seemed to suit the strengths of different cars.
Friday's sessions are rarely a reliable indicator of genuine race pace as they are usually used to assess fuel loads and evaluate any changes the teams make to their cars' set-ups.
Button certainly put in the hard yards in his Brawn, the Englishman completed a mammoth 45 laps as he sought to iron out his earlier problems with both oversteer and understeer.
McLaren's Lewis Hamilton, who famously clinched the 2008 drivers' title in a last lap drama at Interlagos, had a more sedate afternoon as he cruised to the 10th fastest lap time.
But the Englishman will be hoping for better in Saturday's qualifying session where his Kers power-boost system should give him an advantage at a circuit where there can be a 10% power deficit due to the 800m altitude.
"We had a good Friday," said Hamilton. "We are not the fastest, but our long runs appear to be quite consistent.
"We are not as quick as the Red Bulls, but, for Brazil - where we haven't traditionally been quick - we are quite happy with the pace we have.
"Kers is worth close to four tenths in qualifying and around half that in the race, so I am optimistic for tomorrow afternoon and think the consistency we showed today will reward us in the race."