Ahead of today's sole practice session, the air temperature is 19 degrees C while the track temperature is 33 degrees. It remains bright - very bright - and sunny.

Ferrari was quickest in both of yesterday's sessions, Kimi Raikkonen in the first and Sebastian Vettel in the second.

The 0.6s gap to the Mercedes duo, particularly in FP2, has led to claims from the German that Mercedes is sandbagging, a suggestion denied by Lewis Hamilton.

On the other hand, Toto Wolff admits that Ferrari is far better at turning on its tyres, both Hamilton and Valtteri Bottas clearly struggling yesterday. Ferrari absolutely destroying its German rival in S2.

As ever, the airwaves were dominated by Romain Grosjean, the Frenchman unhappy with just about everything.

His team tried the Carbone Industrie brakes in FP1, but it is understood the American team has now reverted to Brembo.

Another team struggling was Red Bull, Max Verstappen insisting that fifth and sixth is the best the team can hope for - the Dutch youngster suffering a fuel pressure issue which sidelined him in FP2.

That said, fifth and sixth is something McLaren-Honda would surely kill for, Stoffel Vandoorne having the dubious honour of being the first driver to pick up a grid penalty this year, the Belgian losing 15-places due to another change of MGU-K and Turbocharger.

After a number of incidents at T2 yesterday, a 'deterrent' has been overnight whereby drivers now have to rejoin the track after driving between two polystyrene blocks.

Magnussen gets proceedings underway, the Dane followed by Ricciardo, Vandoorne, Grosjean, Palmer and Raikkonen.

Seven minutes in and all bar Vettel, Ericsson, Hulkenberg, Sainz and Wehrlein have been out.

Ocon posts the first time of the day, the Frenchman crossing the line at 1:38.373. Moments later teammate Perez posts 38.305.

A 38.207 sees local hero Kvyat take the top spot, all three times thus far posted on the supersofts.

Ricciardo and Raikkonen are on track again, both on ultras.

Quickest in the first two sectors, as you would expect, Ricciardo crosses the line at 37.547, only 0.380s ahead of Ocon who had just improved. Indeed, Perez improves and is only 0.147s off Ricciardo's pace.

As Raikkonen aborts his lap, Verstappen goes quickest, but only 0.052s quicker than his teammate.

Following an earlier slide for Magnussen, now Kvyat spins at T15.

Sainz (supers) goes third (37.692), just 0.197s off Verstappen's time.

That's more like it, Raikkonen bangs in a 35.610, leapfrogging Verstappen by 1.8s. Moments later Vettel posts 35.801, like his teammate he is on the purple-banded rubber.

Ricciardo improves but remains 1.136s off Raikkonen's pace.

The Mercedes duo head out, both on the ultras.

Stroll is also on track on the ultras, the Williams driver not having run them yesterday.

Bottas splits the Ferrari duo with a 35.623 but moments later Vettel responds with a 34.933.

Fastest man of the supers is Sainz who is sixth, albeit 2.3s off the pace.

Hamilton posts 35.700, which is 0.767s shy of Vettel's pace-setter.

"Oh my god, I got a lot of traffic," says Massa, "I almost crash."

"There's about one second between all the compounds here, which should make the ultrasofts the tyre of choice for qualifying," says Pirelli.

Bottas improves with a 35.35 to go second, but remains 0.420s off that lap by Vettel.

Reporting a bad vibration from his engine, Palmer then claims he has lost power.

Massa posts 37.073 to go seventh, the quickest supersoft runner.

With Magnussen, Vandoorne and Palmer still to post a time, Alonso posts 38.533 to go 14th.