Ahead of today's practice session the air temperature is 28 degrees C, while the track temperature is 45 degrees.

As expected, Mercedes dominated both sessions yesterday, Lewis Hamilton heading teammate Nico Rosberg in both.

However, it was behind these two that the battle is shaping up nicely, the next eight drivers covered by just 0.442s indeed, the third through to twelve covered by 1.006s.

As ever drivers were struggling for grip, many feeling that the tyre choice is too hard, while the options (soft) while around 2s quicker than the prime seem pretty durable.

Kimi Raikkonen and Pastor Maldonado were both caught out by the new kerbing at T4, both drivers having their car launched into the air, the return to earth having no doubt caused some loose fillings, or, in the Iceman's case, back pain. Consequently, after words at the Driver Briefing yesterday, Charlie Whiting had the kerbing modified overnight. Pity we don't have a few Charlie Whitings in local government.

The lights go green and Vergne and Maldonado lead the way, soon followed by Ericsson, Alonso, Sutil, Kvyat and Raikkonen. Both Ferraris out early.

The Red Bulls and Toro Rosso are running brand new Renault engines - the core internal combustion engine - which have been introduced, to comply with the regulations, for reasons of reliability.

As was the case yesterday, the Williams duo don't appear particularly eager to get to work, nor their McLaren counterparts.

While most return to the pits after a sole installation lap, Sutil stays out to post the first time of the day (44.515). It was a scrappy lap with mistakes in T4 and T10, the Sauber driver no doubt glad of those modifications overnight.

As Sutil heads back to the pits, Maldonado, Ericsson and Grosjean head down the pitlane.

Ericsson posts 42.360 to go quickest, giving an idea of how scrappy Sutil's lap was, the German not helped by the Sauber's weight.

Maldonado goes quickest (41.275) and Grosjean second as Ericsson complains that he hasn't got enough power on the straight. Meanwhile, Grosjean complains that he has no front grip.

As Ricciardo goes quickest (39.672), Raikkonen heads down the pitlane. Moments later Gutierrez goes second with a 40.425.

As Kvyat and Raikkonen trade fastest sectors, Vergne goes second (40.223). Moments later the Russian posts 38.666 while a mistake in S3 means the Finn can only manage 46.136.

Drivers continuing to lock-up and run wide, as Raikkonen improves to 38.991. Alonso goes third and Vettel fourth.

After twenty-two minutes Magnussen finally leaves the pits but still no sign of his teammate or the Williams. The Finn's first flying lap, the first posted by a Mercedes powered car, sees him go fifth (39.585).

T11 is catching out a lot of drivers, the situation not helped by a strong tailwind.

Tailwind or not, on his first flying lap Hamilton posts 37.340, over 1.3s quicker than the previous best (Kvyat). Moments later Button goes second, 0.957s down on the Mercedes.

Hulkenberg, widely tipped for a podium here, goes third with a 38.422 as Grosjean continues to complain about grip... or lack of it. "I don't know whether it's the tyres or not," he moans.

A 37.252 sees Rosberg go quickest, eclipsing his teammate by just 0.088s.

At half-time, it's: Rosberg, Hamilton, Button, Hulkenberg, Kvyat, Perez, Raikkonen, Alonso, Vettel and Magnussen.