Ahead of today's sole practice session, the air temperature is 30 degrees C, while the track temperature is 34 degrees.

Lewis Hamilton led Mercedes 1-2s in both of yesterday's sessions, though Red Bull and Ferrari were not far off the pace, which is good news for Hamilton.

Other than two punctures for Daniil Kvyat, which meant Toro Rosso also restricted Carlos Sainz' running, there was little of note to report, other than Romain Grosjean's unhappiness with a car that continues to suffer brake issues.

Sebastian Vettel had a gearbox failure in FP2 but the German didn't seem unduly worried, insisting it shouldn't have any impact on his weekend.

Pole is absolutely vital here so we can expect drivers to be looking to get the most out of their one lap sims in the latter stages of this session.

According to Pirelli, the drivers are chasing a moving target in terms of set-up and strategy as the track is constantly evolving.

The lights go green and Grosjean leads the way, followed by Vettel, Gutierrez, Kvyat, Raikkonen and Button. All bar the Russian are on ultras.

Kvyat complains of a "vibration under braking".

"This isn't a particularly relevant session as qualifying (and race) conditions will be very different," admits Pirelli.

Kvyat posts the first time of the day (1:49.113) but this is soon beaten by Perez who posts 44.046. The Mexican, like the Russian, is also on the supersoft.

Asked if he thinks there is more in the tyre, Perez says "yes", he adds, "I also think I have a good read of the car."

As Verstappen posts 42.461, Wehrlein complains of a bad vibration following a lock-up. The wobble in his voice supports the severity of the vibration.

As the Mercedes duo head out, Ricciardo goes second with a 42.609. The Australian is told that he's losing out to his teammate at T6.

Despite that vibration, Wehrlein goes fourth (45.055), only to be demoted by his teammate (Ocon) who posts 44.882.

A 42.695 sees Rosberg go third, as Hamilton goes quickest in S1. Going quickest in the final sector also, the Briton crosses the line at 42.120.

Bottas goes fifth and Massa sixth, as Ricciardo (42.401) leapfrogs his Red Bull teammate to go second.

On his first flying lap Vettel posts 42.034 to take the top spot, albeit by just 0.086s. However, whereas the Mercedes and Bulls are on the supers, the Ferrari driver, like the Williams duo, is on ultras.

Reporting a loss of power, Hamilton is told it was an "unexpected loss of D-rate". Which is comforting.

As Vettel improves to 41.957, Alonso goes 8th with a 43.797.

Hamilton heads back to the pits for a cautionary check as Sainz spins at T18.

Rosberg improves (42.176) but remains third.

Raikkonen's first flying lap sees the Finn go sixth (42.785), having lost time in T3 after making a mistake and running slightly wide.

Rosberg complains that his car is pulling to one side under braking, and asks his crew to check it out.

As Button posts 43.716 to go ninth, Hulkenberg remains the only driver yet to post a time. Indeed, the German doesn't look like coming out any time soon.

Raikkonen posts 41.700 to go quickest by 0.131 - Ricciardo having improved to second on the ultras - as Grosjean launches into another tirade about the Haas. "The car is on the nose," says the Frenchman. "I can't do anything."

"The Hulk joins the party!" declares Force India as, thirty-five minutes into the session, the German finally emerges. On the supersoft he goes on to post 43.576 which puts him ninth.

The Mercedes duo emerge on ultras as their qualifying sims get underway.

Though quickest in the final sector, Rosberg loses pace in S2. He finally crosses the line at 41.168, which is 0.532s quicker than Raikkonen. However, Hamilton responds with a 41.065, despite not going purple in a single sector.

With 20:00 remaining, the Toro Rosso duo remain at the bottom of the timesheets having completed just 7 laps between them.

Like Ricciardo yesterday, Hamilton is told to "compromise T8 for a better T9".

Sainz heads out again as the Mercedes duo enjoy a 0.5s comfort cushion to the nearest opposition (Raikkonen).

Hamilton goes purple in S2 but fails to improve overall as Sainz returns to the pits.