Button's lap highlighted the progress made by BAR, and was overheard in the garage telling his engineer: "I can go quicker". Montoya, meanwhile, will be hoping that this is the weekend he can get his title bid properly on track.

Ferrari was toppled from the head of the times for the first time this weekend as the Michelin runners came on strong. Both Michael Schumacher and Rubens Barrichello suffered dusty offs early in the session (and showed a healthy respect for Bahrain's over-sized kerbs when rejoining) but bounced back to take the third and fourth fastest times respectively. They were almost half a second shy of the leading pace, however.

Another major talking point from the session was McLaren's David Coulthard, who suffered his second puncture of the weekend. This was not as dramatic as yesterday, but the deflation of his right front under braking for one of Sakhir's many tight bends will be a concern to Michelin.

McLaren team-mate Kimi Raikkonen was sixth fastest, getting in 14 laps after yesterday's engine disaster. He was four tenths slower than fifth placed man, Ralf Schumacher of Williams. Takuma Sato was seventh for BAR, one spot ahead of the troubled Coulthard, while Renault duo Fernando Alonso and Jarno Trulli rounded out the top 10.

Christian Klien, a star of Friday, was 11th for Jaguar, and lucky to escape the gravel trap after a big spin. He outpaced team-mate Mark Webber once again, this time by six-tenths, in his most impressive showing to date.

Toyota's Olivier Panis and Cristiano da Matta were 12th and 13th, ahead of Sauber's Giancarlo Fisichella. His team-mate, Felipe Massa, was forced to sit out the entire session after grinding to a halt on his out lap.

Behind 15th placed Webber, Jordan duo Nick Heidfeld and Giorgio Pantano predictably outpaced the Minardis of Gimmi Bruni and Zsolt Baumgartner.