Ahead of today's all important qualifying session, the air temperature is 22 degrees C, while the track temperature is 28 degrees. It remains bright and sunny.

With yesterday's session all but washed out, this morning's one hour session was as busy and crucial as expected. However, it appeared to pose more questions than it answered.

Unable to get a clear run in the final phase, thanks mainly to Jaime Alguersuari, Sebastian Vettel was unable to post a competitive time in qualifying spec. On the other hand, Jenson Button, who is running a new chassis today, went quickest on a set of option (supersoft) tyres on which he had already completed a number of hot laps. Teammate Lewis Hamilton was also looking good however, on his final flying lap he lost time behind Michael Schumacher.

The lack of (dry) running means that tyre wear is a grey area, with some wildly differing opinions as to how many stops might be required tomorrow.

Therefore, the big question this afternoon is will we see a car other than a Red Bull on pole for the first time this season, indeed, for the first time since Brazil last year? Then again, the odds were very much against the Austrian team going into last week's session only for Vettel to take his twelfth pole of the season… with a little unintended help from Lewis Hamilton.

Leaving the Red Bull-McLaren battle aside, Ferrari is looking strong this weekend, particularly Fernando Alonso who has a new front wing at his disposal, while Mercedes is also looking useful.

After a couple of disappointing races Renault is looking for a better result this weekend, birthday boy Bruno Senna, in particular, looking for a decent tally.

With the Constructors' Championship all but decided - does anyone really expect McLaren to overhaul a 130 point deficit? - interest focuses on the battle for sixth between Force India, Sauber and Toro Rosso, while Williams desperately needs to grab a further point or two before season's end.

Tyre options are soft (prime) and supersoft (option), while the DRS zone for tomorrow's race is on the straight between Turns 2 and 3.

The lights go green for Q1, and after a few seconds birthday boy Senna heads down the pitlane. The Brazilian is subsequently joined by Petrov, di Resta, Perez, Ricciardo, Liuzzi and d'Ambrosio.

Senna, who had a slight brush with the wall this morning after spinning, posts a 39.951 but this is soon beaten by Petrov's 39.406. Hamilton, Button and Webber leave their garages. Vettel is another early rise, curiously, both Red Bull drivers are on the options even at this early stage.

As Hamilton begins his first flying lap, Senna goes quickest in S1. The Englishman goes quickest in S2 subsequently crossing the line at 38.278 to take the top spot.

Button goes second with a 38.768 only to be demoted by Massa (38.670), while Webber goes fourth (39.071).

Alonso, sporting the new front wing, goes second (38.393), while Vettel, on the options, can only manage sixth (39.093). However, are the Red Bulls running with a heavier fuel load?

As both Red Bulls pit, Hamilton, following a 'slow' lap, ups the ante and goes quickest in the first two sectors of his next lap. At the line it's 37.525 as Rosberg goes fourth and Schumacher sixth.

Button improves to second with a 37.929, and with 9:10 on the Williams duo have yet to post a time. The Grove outfit leaving it very late. Ricciardo has been out but has not yet posted a time.

As Barrichello leaves the pits, former teammate Schumacher goes fifth with a 38.502.

4:45 on the clock and while Hamilton, Button and Alonso appear to have settled for their times, the majority of their rivals haven't and are back on track.

Petrov posts 38.378 to go third as Barrichello begins his first flying lap. The Brazilian posts 39.538 to go fourteenth. Moments later, teammate Maldonado goes sixteenth (39.952).

Kobayashi drops into the danger zone, as teammate Perez goes tenth. The Japanese driver improves but can only manage fifteenth (39.464).

Di Resta improves to seventh and teammate Sutil ninth, as Ricciardo remains in the pits, his session over before it began.