Ahead of today's sole practice session - this being a Sprint weekend remember - the air temperature is 18 degrees C, while the track temperature is 36 degrees. It is cool and cloudy with the threat of rain. Indeed, there is a 60% chance of rain.

The big question, or rather one of the big questions, heading into the weekend is whether Lewis Hamilton will add a fresh engine to his pool and thereby incur a grid penalty.

While Mercedes remains as tight-lipped as ever, British tabloids such as the Express, Daily Mail and, God help us, the Evening Standard, insist the decision is made and the world champion will take the hit.

Time will tell.

This being a Sprint weekend, the drivers have just this one session before going into qualifying, which could well compromise those, like Schumacher, Mazepin and Tsunoda who have never raced here before.

What with qualifying this afternoon and the prospect of rain, the engineers face a real conundrum in terms of set-up, especially as Sunday looks likely to be dry.

The lights go green and Stroll leads the way, followed by Raikkonen, Norris, Giovinazzi and Alonso. Bottas is among the early risers. A mixture of hards and mediums.

Raikkonen posts the first time of the weekend, a 14.960, while Giovinazzi posts a 16.376.

As Verstappen reports a vibration on his tyres, Mercedes confirms that Hamilton has taken on a new ICE and therefore incurs a 5-place grid drop.

So, those tabloids were correct (for once), though not in terms of the 10-place drop they were reporting.

Verstappen crosses the line at 11.482 as the times get sensible, as Perez posts an 11.774 before being demoted by Bottas (11.540).

Verstappen improves to 10.853 while Hamilton goes 6th with a 12.613.

The world champion subsequently posts 11.897 to go fourth, ahead of Alonso, Ocon, Tsunoda, Sainz, Leclerc and Gasly.

As Hamilton complains his front end is "really poor", Verstappen improves to 10.189.

Gasly leapfrogs Hamilton for fourth with an 11.834.

Though nothing like Mexico, Interlagos is a high altitude circuit and is therefore likely to favour the Honda, as was the case a week ago when the Japanese manufacturer filled three of the top four positions.

Ocon goes third with an 11.657.

Twelve minutes in and neither of the Aston Martin drivers has posted a time.

Benefitting from a tow on the pit straight, Hamilton is quickest in S2, the Briton crossing the line at 11.038 to go second, albeit 0.8s off Verstappen's pace.

Vettel goes sixth (11.743) on the hards, the only quicker driver on the white-banded rubber being Ocon (11.345).

"Please come up with another solution," pleads Hamilton.

Side-by-side on the pit straight, Hamilton score an early psychological point over Perez. That said, the Mexican subsequently posts a 10.803 to go second.

Leclerc locks-up in Turn 1, the Ferrari driver currently 12th on the hards.

Perez closes to within 0.020s of his teammate with a 10.209.

An 11.692 sees Stroll go seventh, just behind his teammate. Moments later the Canadian reports: "It's drizzling a bit".

While Hamilton has completed 16 laps and Bottas 18, Verstappen is the only driver on single figures, such would appear to be his confidence. Teammate has completed 12 laps.

"The fronts are bouncing across the track," sighs Hamilton.

Twenty-eight minutes in the track is declared "wet" though the drivers stick with the mediums and hards.

Replay shows the Mercedes pair almost coming to grief in the pitlane. Staring at his monitor Toto looks less than impressed.

Switching to mediums, Leclerc goes quickest in S1 as Sainz (also mediums) goes third overall with a 10.624. Leclerc subsequently posts a 10.194 to go second.

The Bulls switch to the red-banded rubber, the first to do so.

Perez is quicker in the opening sector, while Verstappen rules the second. At the line Verstappen posts a 9.417 while his teammate responds with a 9.492. Just 0.075s separates them.

Bottas and Schumacher are the next drivers to switch to softs.

Setting a strong pace in S1, Bottas backs off in the second sector. On his next flying lap he is already two-tenths down in the opening sector. A PB in S2 is followed by a third as the Finn posts a 9.867 to go third, 0.45s off the pace.

In the Mercedes garage, the mechanics are working on the front suspension on Hamilton's car.

As Alonso goes fifth on mediums, Hamilton heads out on softs. PBs in the first two sectors see the world champion stop the clock at 9.768 to go third, 0.351s off the pace.

On the softs, Russell improves to 12th as Bottas heads out again and immediately goes quickest in the opening sector. At the line the Finn, on 8 lap old rubber, posts a 9.567 to go third.

Latifi goes 11th on the softs, as more drivers switch to the red-banded rubber.

On fresh softs, Hamilton goes quickest in S1 as Ocon goes fifth overall on mediums. A tow from Mazepin on the pit straight is enough to see Hamilton improve to 9.348 to go top. However, prior to that tow, the Mercedes driver could only manage a PB in the second sector.

Sainz goes quickest in S1 as teammate Leclerc posts a PB. At the line the Spaniard posts a 10.124 to go fifth, while Leclerc can only manage sixth (10.142) after running wide in Turn 4.

Leclerc fears he damaged his car on the kerbs after that off in Turn 4.

Seventh and eighth, Ocon and Alonso persist with the mediums.

On 4-lap old softs, Hamilton goes quickest in S1 and S3 raising the bar with a 9.050. Elsewhere, Alonso and Gasly appear to think its Sunday - or Saturday afternoon - as they battle all the way along the pit straight and into the Senna Esses.

Moments after Bottas runs wide in Turn 13, Verstappen follows suit taking a punishing ride over the kerbs.

Hamilton beats the clock, crossing the pit lane exit line seconds before the chequered flag.

The session ends. Hamilton is quickest, ahead of Verstappen, Perez, Bottas, Gasly, Sainz, Leclerc, Ocon, Alonso and Stroll,

Tsunoda is eleventh, ahead of Vettel, Raikkonen, Giovinazzi, Norris, Schumacher, Latifi, Russell, Ricciardo and Mazepin.

While this is usually the point where we'd be commenting that the session has posed more questions than it answered, the fact that it is the only session before qualifying has only added to the conundrum.

If nothing else, what happened to McLaren, Norris and Ricciardo finishing 15th and 19th.

With that grid penalty the pressure is on Hamilton to set the pace again this afternoon, and as Red Bull continues to pay attention to Verstappen's rear wing, getting a tow is likely to be a major player in this afternoon's session.

Check out our Friday gallery from Interlagos, here.