Ahead of today's opening practice session the air temperature is 23 degrees C, while the track temperature is 36 degrees. It is bright and sunny, however that it unlikely to be the case for the entire weekend. Indeed, there is a 10% chance of rain over the next 45 minutes.

There are two reserve drivers on duty this morning, Charles Leclerc at Sauber and, making his FP1 debut, Mercedes protégé George Russell at Force India.

At Haas, Antonio Giovinazzi was scheduled to run in this session but will instead run in FP2, the American outfit wanting Kevin Magnussen in the car for this session as it fears rain this afternoon.

The lights go green and Ricciardo, who has been waiting at the end of the pitlane for over three minutes, gets proceedings underway.

"Can you sing us a song or something?" asked Ricciardo as he waited. "You could always sing knock, knock, knocking on Renault's door," came the reply.

He is joined by Vettel, Ericsson, Alonso and Leclerc.

Hamilton and Bottas are the last out, as Verstappen posts the first time of the weekend, the Red Bull driver posting a 12.253.

Mercedes has admitted that having secured both titles, this race weekend, and that in Abu Dhabi, will be used for experimentation with an eye on 2018. No doubt, for the same reasons, rival teams will be following suit.

While the rest return to their garages, Verstappen stays out, improving to 11.491. He is told to keep some temperature in his front tyres as he subsequently raises the bar with a 10.959.

There's no messing about at Mercedes, as on his first flying lap Bottas pumps in a 10.820.

The Finn is on the yellow-banded soft rubber, while Verstappen is on the supersoft.

As Bottas improves to 10.102, Ricciardo (sofs) goes third (11.154) and Vettel fourth (12.385).

The VSC is deployed as Hartley pulls off trach at T15, smoke billowing from the rear of the Toro Rosso following another engine failure... back to F1 reality for the newly crowned WEC champion.

"I have big smoke, big smoke," Hartley tells his engineer, and he isn't talking about a celebratory cigar.

In no time at all, the VSC is withdrawn again as the Toro Rosso is pushed to safety.

Vettel improves to 10.321 as Raikkonen goes sixth with an 11.617. Both Ferraris on the supersofts.

On his first flying lap, Hamilton posts 1.174 to go second, while Vettel is off and on the grass at T9. Replay reveals little, the back of the car just suddenly stepping out.

The German claims he "pushed a little bit too hard in 8" and "lost the rear in 9".

Bottas improves to 9.941 but is instantly deposed when Hamilton stops the clock at 9.672.

Vandoorne goes an impressive fourth with a 10.711, as Massa goes fifth (10.755).

After 30 minutes of running, we have yet to see times from Ericsson, Alonso, Leclerc, Hartley or Russell.

A mistake from Hamilton sees the Briton run wide in T1, making full use of the seemingly endless run-off.

The Mercedes pair continues to trade fastest times, both still running the softs rubber. The next highest placed soft runner is Ricciardo (5th) then Ocon (9th), who is 1.711s off the pace.

Russell's first flying lap sees the Briton go 15th with a 13.321.

Magnussen, on softs, complains that his rears are "already gone".

At 40 minutes, as the drivers hand back their extra set of tyres, it's: Hamilton, Bottas, Massa, Vettel, Ricciardo, Verstappen, Vandoorne, Raikkonen, Ocon and Stroll.

Following the traditional several minutes of nothing, A Ferrari engine fire-up fills the air and Ericsson heads out.

Since Hartley's engine issue, teammate Gasly has been confined to barracks, the Faenza outfit clearly fearing more problems. Indeed, the Frenchman is out of his car and out of his overalls.

Now on the supersofts, Bottas improves to 9.329.

Quietly getting on with things, Alonso improves to seventh with a 10.476.

A 9.984 sees Vettel take third from Massa, but the German remains 0.78s off the pace, Hamilton having just raised the bar with a 9.202.

Raikkonen leapfrogs his teammate with a 9.744, but still remains 0.5s off the pace of the leading Mercedes on the same rubber.

Despite his awesome pace, Hamilton is told he is "too deep at Turn 8".

A 9.750 sees Verstappen go fourth, as Massa goes sixth with a 10.102.

"That was very dangerous of Hulkenberg," says a remarkably calm Hamilton after running wide and onto the grass after being passed by the German who was on a hot lap.

As drivers focus on longer runs, Hamilton is advised that nobody is improving on the supersofts.

"What lap time should I be aiming for," asks a remarkably calm Russell. He is advised that he is currently 0.9s off Ocon's pace.

With Toro Rosso out of the running, the Saubers and Renaults are well down the order, while the Haas duo are also around 2s off the pace.

Toro Rosso confirms that Gasly suffered an MGU-H issue as the cameras pick up on Hartley who is still out on the infield with his car.

An 11.047 sees Russell close to within 0.6s of Ocon. The Briton complains that it feels as if his balance is changing without touching it.

Ricciardo is advised that his pace on his used supersofts is matching that of Bottas. That's probably just as well as the Australian faces a grid penalty on Sunday, as do both Toro Rosso drivers.

Verstappen is unhappy with his car. Told to focus on controlling the car into Turns 10 and Turn 12, and the exits, the youngster replies: "I'm trying, but if there's no grip, I can do whatever I want but it's not going to change anything."

A PB in S3 for Alonso as the McLaren benefits from a tow from Verstappen up the hill.

Alonso told to "attack the pit entry" as the team prepares for a practice live pit stop.

Vettel clearly unhappy with Sainz after the Spaniard impedes him in T2.

Onboard shows Bottas running wide while Verstappen has a badly blistered front-left.

Told to "keep pushing", Leclerc argues: "Well I couldn't, Ocon was in front of me on a race sim, so I couldn't keep pushing." He omits to add "so there!"

As the session ends, Bottas complains of a flat-spot that is causing a vibration which is affecting his vision.

Hamilton is quickest, ahead of Bottas, Raikkonen, Verstappen, Ricciardo, Vettel, Massa, Vandoorne, Ocon and Alonso.

Stroll is eleventh, ahead of Russell, Grosjean, Magnussen, Sainz, Hulkenberg, Leclerc, Ericsson, Gasly and Hartley.

Check out our Friday gallery from Interlagos, here.