Ahead of today's all-important qualifying session the air temperature is 24 degrees C, while the track temperature is 32 degrees. It remains bright and sunny.

Williams Nico Rosberg has set the pace in every session thus far, therefore the big question is can he maintain this pace in qualifying and then the race? Williams is one of three teams - the diffuser dissidents as we call them - to have exploited a loophole in the regulations and come up with a device that has its rivals seething with rage at what they see as gamesmanship, yet green with envy that they didn't come up with it.

The fact that all six drivers using the 'special' diffusers have been at the top of the timesheets for much of the weekend, suggests that along with Williams, Toyota and Brawn must figure as potential pole-grabbers not to say race winners, however, will the rival teams, realising that they have little else to lose, throw caution to the wind, adopt a special pole-at-all-costs qualifying strategy and spring a surprise. We'll soon know.

Of special interest, especially in the early stages of the session, will be the pace of Kimi Raikkonen, who completed just 5 laps this morning, not to mention McLaren, BMW and Renault.

The lights go green, however, unlike the previous sessions, there is no queue in the pitlane. Just over a minute later, Fisichella heads the pitlane followed by Buemi and Rosberg. Raikkonen is another 'early bird' as are the Williams boys.

Fisichella crosses the line at 1:28.840, but Massa, Rosberg and Sutil are already on very, very fast laps.

Rosberg goes quickest with a 27.833 as Massa goes second, moments later however, Sutil goes second with a 8.114. Raikkonen goes sixth.

On his second flyer, Rosberg improves with a 7.083, as Buemi momentarily goes second with a 27.949 before being bumped down by Massa.

A 26.752 sees Nakajima go quickest, as his teammate goes wide. Elsewhere, Raikkonen goes third with a 27.254. On his next lap the Finn goes quickest in the first sector, finally crossing the line at 6.615 to take the top spot.

Barrichello goes fourth as Hamilton goes out on the softer option tyre. Webber goes third, splitting the Williams.

From out of nowhere, Alonso produces a 26.474 to go quickest, however, Barrichello is on a hot lap having gone quickest in the second sector. The Brawn driver crosses the line at 26.247 to go quickest.

Hamilton goes second (26.454) having gone quickest in the second sector, however, all eyes are on Button. The Englishman crosses the line at 26.253 to make it a Brawn 1-2 as teammate Barrichello improves to 25.815.

Rosberg improves again to split the Brawns as Glock posts 26.648 to go fifth. The diffuser dissidents fill four of the top five positions.

With just over six minutes remaining, Massa and Kubica are in the drop zone, with Kovalainen far from safe.

Kubica improves to fifth, as Massa goes quickest in the first sector. Trulli still in eighteenth.