Ahead of today's all-important qualifying session, the air temperature is 33 degrees, while the track temperature is 39 degrees.

Following the three somewhat unusual free practice sessions, particularly this morning's, this is probably the first opportunity we'll have to gauge the real form of the various teams and drivers.

The lights go green, and Sebastien Bourdais leads the way, followed, a minute or so later, by Glock, Vettel, Davidson, Sutil and Fisichella.

Bourdais posts the first time of the session, the former Champ Car star crossing the line at 30.250. moments later, however, he is upstaged by Fisichella and Vettel. However, next time around Bourdais retakes top spot with a 27.446.

Glock, who has had a gearbox change to his Toyota, is really hanging out the tail of his car, it wastes time but looks superb.

After eight minutes of the twenty minute session only eight drivers have posted times. The rules have been changed yet again, but we still have to suffer these periods of inactivity as the drivers wait for the optimum moment to run.

The second wave gets underway, Alonso, Piquet, Rosberg, Coulthard, Webber, Trulli, Button, Barrichello, Hamilton and Kovalainen. No sign of the Ferraris or BMWs.

Trulli goes quickest with a 27.077, but he is quickly demoted by Rosberg, as Alonso goes second ahead of Webber. It is fast and furious, as ever.

A 25.664 sees Kovalainen go quickest, but his McLaren teammate is on a hot lap. Following a mistake, the Englishman can only manage second, crossing the line at 26.572.

The BMW duo leaves the pits with seven minutes remaining, followed, shortly afterwards by Massa.

Vettel (soft) goes third, but is displaced almost instantly as Kubica goes second. Heidfeld has a poor lap as Raikkonen leaves the pits.

Kubica goes quickest in the first sector, but then loses time behind Raikkonen who is on his out lap.

Massa goes quickest in the first sector, as Heidfeld goes second overall. The Brazilian crosses the line at 25.994 to go third.

Just over three minutes remaining and Raikkonen goes fifth (26.140).

Kovalainen, Heidfeld, Massa, Kubica, Raikkonen and Hamilton, as the final assault of this phase gets underway.

Raikkonen is going very, very slowly. At first it looks as though he's slowing for a Toro Rosso, but as it sweeps by it becomes apparent that it is a problem with the Ferrari.

Coulthard goes sixth as Adrian Sutil spins in the final sector, his Force India stranded in the middle of the track. This couldn't happen at a worse time. Barrichello has moved up to seventh, while Piquet is stuck down in twenty-first, a nightmare debut for the Brazilian.