Ahead of today's second free practice session, the air temperature is 23 degrees C, while the track temperature is 32 degrees. It is bright and sunny with the humidity now dropped to 59%.

This morning, the Red Bull duo was head and shoulders ahead of the opposition, both drivers over a second clear of their nearest rival, Robert Kubica. It remains to be seen whether the gap can be closed this afternoon, or maybe even extended.

This morning was something of a test session for most of the teams, especially Mercedes, which chopped and changed between various aero packages, a move which saw the teams changing the floors on both cars.

The flexing front wing on the Red Bull was a clear advantage this morning, and therefore Ferrari is to run its version this afternoon.

The lights go green and Yamamoto is first out on track, the Japanese driver being advised that there is a strong headwind. Vettel and Webber are among the first out.

Yamamoto posts the first time of the afternoon, the Japanese driver crossing the line at 29.317, however, moments later his countryman, Kamui Kobayashi, posts 24.574.

Having gone quickest in all three sectors, Petrov takes the top spot with a 22.490 while Hamilton posts 24.144 to go third behind Hulkenberg.

Just eight minutes into the session there are already fifteen names on the timesheets, Button going second (22.853) and Hamilton third (22.859).

As Barrichello goes quickest with a 1:22.468, Button complains that the "traffic is a nightmare".

Hamilton goes quickest with a 22.373 but Alonso is on a hot lap having already gone quickest in the second sector. He's quickest again in S3, crossing the line at 21.826.

"There's a vibration on my helmet," complains Rosberg. The German one of five still to post a time.

Having gone quickest in S3, Massa goes third overall with a 22.316 however, Vettel and Webber are both on track.

Alonso raises the benchmark with a 21.743 as Sutil gets alarmingly out of shape.

Webber goes sixth with a 22.422 having gone quickest in S3. Moments later Vettel posts 22.820 to go eleventh.

Next time around, ominously, the Red Bulls go 1-2 with Webber posting 21.046 and Vettel 21.324. Behind them, are the two Ferraris and the two McLarens.

Webber raises the benchmark with a 20.881 but the Ferraris are only 0.6s off the pace. Vettel, determined not to be outshone by his Red Bull teammate, posts 20.773.

With an eye on Sunday, driver now concentrate on longer full fuel runs, as opposed to seeking fast sector times.

Coming up to half-time, Webber goes quickest is S2 and S3, crossing the line at 20.601. Other than Kovalainen, who has posted 5 laps, the Mercedes duo have completed the least laps, Rosberg and Schumacher having done just 17 laps between them.

Hulkenberg and Kobayashi are the first drivers to switch to the option (super-soft) tyre, the German going sixth (21.794) and the Japanese driver eleventh (22.338).

Hamilton is on track on the option tyre, the first of the big guns to make the switch. Having posted personal bests in the first two sectors he can still only manage 21.308, which is 0.707s off the pace of the Red Bulls, which were on primes.

Now Webber is on track on options, as is Schumacher. The German runs wide in the final corner, crossing the line at 21.773 to go eighth.

Massa kicks up a cloud of dirt as he runs wide at Turn 7, meanwhile, Webber fails to improve his time.

Alonso (option) goes quickest in S1 but loses time in S2. Moments later, Webber goes quickest in S2. Having gone quickest also in S3, Webber consolidates his top spot but only by 0.004s.

All eyes on Webber who is now on the option tyre, as Kubica goes seventh with a 21.469.

Alonso splits the Red Bulls with a 20.715 but moments later Vettel posts a 20.089 beating his teammate by 0.510s. Awesome.