Ahead of today's sole free practice session, the air temperature is 19 degrees C, while the track temperature is 22 degrees. It is bright and sunny, entirely different from yesterday, when the damp and greasy conditions caused all manner of problems, particularly in the morning.

While Michael Schumacher was the pace-setter yesterday, certainly in the second session, there remains doubt as to Mercedes ability to get the best out of its tyres, particularly on race day.

Lewis Hamilton was quickest in the opening session, however, he faces a five-place grid penalty after his team changed the gearbox in his car, as was widely anticipated.

While Red Bull seems a lot happier here than in Australia and Malaysia, it was back to earth with a bump for Ferrari, the team realising that there is still much to be done and that the Sepang was result was a fluke, albeit following a typically great drive from Alonso.

Following his off in the second session, which the team stresses was not due to a mechanical failure, Timo Glock has been declared fully fit, the German complaining of a sore hand in the aftermath of the incident.

Sebastian Vettel is sticking with his old exhaust layout, while his teammate prefers the new version. Ferrari is also happy with its new wing.

The lights go green and Kovalainen leads the way, followed by Kobayashi, Karthikeyan, Vergne, de la Rosa, Grosjean, Ricciardo, Petrov, Glock and Perez. All are on the prime (medium) tyres.

Within the first couple of minutes all but Vettel, Alonso and Hamilton have been out, their rivals all having returned to the pits after that sole installation lap, much like we normally see on a Friday.

Once the three - Vettel, Alonso and Hamilton - have been out, there follows several minutes of total inactivity - again, much like a Friday. At 48.50, Karthikeyan breaks the deadlock, followed by Grosjean, Petrov and Perez.

As Grosjean posts 38.126 and Perez 37.853, more drivers pour on to the track. Renault not having really shown its hand yesterday, is said to be much happier with today's conditions, especially the fact that it is less windy. As if to prove the point Raikkonen posts 37.276 to go quickest.

On his first flying lap, Rosberg goes second (37.382), leaving Massa, Alonso, Button and Hamilton as the only drivers yet to appear for a second run. Schumacher demotes his teammate with a 37.376.

McLaren has made a number of adjustments to Button's car, the Englishman extremely unhappy with its handling yesterday, it's surprising not to see the Briton out there evaluating them.

A 37.363 sees Webber go second, Raikkonen still holding on to the top spot. That said, a 36.985 sees Rosberg go quickest. Elsewhere, Schumacher has a big wobble in Turn 1.

Webber goes quickest in S2, subsequently crossing the line at 36.879, out-pacing Rosberg by 0.106. Elsewhere, Vettel's front-right locks up in Turn 6, leaving the German totally mystified.

Massa, Button and Hamilton all on track now, with Alonso joining them shortly after.

Hamilton goes fourth (37.338), Massa twelfth (38.266) and Button seventh (37.639), as Rosberg runs wide in Turn 1. Alonso subsequently posts 37.724 to go tenth.

In the Red Bull garage the mechanics are working on the brakes on Vettel's car, also changing the torsion bar, the German having previously complained about the car's handling under braking. Teammate Webber is still quickest, ahead of Rosberg, Hamilton, Raikkonen, Schumacher and Kobayashi.

F1's latest gimmick, the helmet-cam, shows di Resta perusing a data read out from the comfort of his cockpit. The Scot, currently thirteenth, had been complaining about a loose rear on his car.

Back on track, Vettel goes quickest in S2, finally crossing the line at 37.039 to go third overall, the German clearly happier with the car after those brake adjustments.

Rosberg is back on track, now on the option (soft) rubber, as is Schumacher, Vergne and Ricciardo.

The Mercedes drivers trade fastest sector times, Rosberg crossing the line at 36.389 and Schumacher 36.512, the Brackley outfit going 1-2.

Schumacher complains about the balance through Turns 9 and 10, as Vergne and Ricciardo pit having only managed tenth and thirteenth on the soft rubber.