Vettel strikes first blow

German Vettel, whose time of a minute 42.760 seconds was six-tenths quicker than second-placed Lewis Hamilton, is third in the standings but one of four drivers capable of winning the crown on Sunday.

His Red Bull team-mate Mark Webber, second in the World Championship table behind Fernando Alonso, was fourth behind the McLarens of Hamilton and Jenson Button.

Hamilton is an outsider for the title, standing fourth, but looked quick with his customary late run in the session.

Ferrari's Alonso struggled to match the pace of the Red Bulls, finishing sixth with a time 1.361s off Vettel's pace and three-tenths off that of Webber.

The first half of the 90-minute session was effectively ruled out by a brief shower just over an hour before the start. Completely unexpected in the dry heat, the passing rain left the track - not built with drainage a key consideration - completely damp.

As the temperatures rose it dried out, but teams were unwilling to risk their cars with only tentative explorations on intermediate tyres for the opening 45 minutes.

Vitaly Petrov set the first timed lap on slick tyres and a host of drivers were soon out and battling for supremacy.

Alonso was top briefly before Webber - bidding to become the first Australian to win the drivers' crown since Alan Jones in 1980 - took over.

Vettel carved nine-tenths off his team-mate's time but Webber responded to retake P1 with 1:43.840; that, set with 25 minutes left on the clock, was to be his fastest of the session.

Vettel went top with 12 minutes left and would improve on it once to move away from Hamilton, who had gone from the bottom spots straight into second with a lap of 1:43.369 as time wound down to put pressure on his rival.

Reigning champion Button - ruled out of the title fight following the last race - suffered problems with his brakes but leapt to third late on to bump Webber down to fourth ahead of Robert Kubica.

Behind double world champion Alonso was Michael Schumacher in the Mercedes, with Kamui Kobayashi of Sauber separating the German from his young compatriot and team-mate Nico Rosberg.

Nick Heidfeld followed in the sister Sauber ahead of Spaniard Alonso's colleague Felipe Massa.

Rubens Barrichello, who ended in 13th, stopped out on track following the chequered flag and had to abandon the Williams.