Ahead of today's sole free practice session, the air temperature is 26.3 degrees C, while the track temperature is 40.2 degrees. It is cooler than yesterday following overnight rain, while the wind has picked up also.

Yesterday witnessed a complete turnaround from what we saw in Melbourne, with Ferrari enjoying a very clear advantage over Mercedes.

However, team boss, Mattia Binotto, was keen to play things down, insisting Ferrari was experimenting with engine modes. While that may well account for the gap, it doesn't hide the fact that clearly Ferrari has made changes since Australia.

While the second session finally saw Lewis Hamilton get the upper hand over his teammate, it was a mixed day for Red Bull, where Max Verstappen was 0.8s off the pace and Pierre Gasly 1.5.

Once again Haas looked strong, only adding to McLaren and Renault's frustration over "B-teams", while the Woking outfit and Toro Rosso looked good, as indeed did Nico Hulkenberg who finished fifth quickest, ahead of Verstappen.

Williams travails continue, while Racing Point suffered, as did Alfa Romeo, both Raikkonen and Giovinazzi losing a lot of valuable track time in the afternoon.

The lights go green and Norris leads the way, followed by Giovinazzi, Grosjean, Albon and Ricciardo.

Setting the timing scree alight with purples, Magnussen dives into the pits, thereby depriving us of the first timed lap of the day.

"DRS is not working," reports Russell. Don't worry George, Patrick Head will soon get that sorted.

All running thus far has been on hards, bar Kubica who is on mediums. However, Vettel, Leclerc and Ricciardo head out on softs, albeit used softs.

No diving into the pits for Vettel, who posts a 31.617, despite running wide in T13.

A strong opening sector is followed by mistakes in the two that follow, meaning that Leclerc can only manage 31.756. Yes, we did say 'only'.

Twelve minutes in and only the Ferrari pair have posted times, the Bulls, Points - yes, Points - and Silver Arrows yet to appear.

Raikkonen goes third (31.761) and Giovinazzi fourth (32.132), while Ricciardo subsequently splits them with a 32.107.

All five times posted thus far have been on the soft rubber.

A wobble for Giovinazzi as the Alfa is caught by the strong wind in Turn 4, despite running wide the Italian does well to hold it all together.

Bottas is the first of the other big guns to head out, like the Ferraris he is on softs, albeit a brand new set.

As Hamilton heads out, on fresh rubber, Bottas goes quickest with a 31.169.

Kvyat goes second, the Russian posting 31.592, just 0.423s off Bottas' time.

A 31.650 sees Sainz split the Ferraris, on medium rubber.

Not just understeer for Grosjean, "but big, big, big, big understeer".

Also on mediums, Norris goes fifth, splitting in behind his teammate.

As Hamilton begins his flying lap, Vettel heads out on fresh softs. Hamilton aborts his lap after losing time behind Stroll.

Despite really fighting the car, Hamilton goes quickest in S1. Elsewhere Bottas consolidates his top spot with a 31.111. Hamilton loses a little pace in S2, finally crossing the line at 31.016 to go top, 0.095s quicker than his teammate.

Yesterday Hamilton complained about the balance of his car, and it is clear that the issue remains.

At half-time we've yet to see a time from Verstappen, though he is now on track. Gasly is currently 15th, 1.119s off the pace.

Hulkenberg goes third with a 31.563. Nonetheless, he is not happy, complaining about other drivers going slow and poor track positioning.

"We have a rear-left puncture," Perez is told.

Straight out of the box, Verstappen, on new softs, goes quickest (30.959), though he is only quickest in the final sector, which is increasingly looking to be the most vital sector.

Not for the first time this afternoon, a marshal takes his life in his hands running on to the track to remove a piece of debris.

With 22 minutes remaining, Leclerc heads out on a brand new set of softs. Vettel didn't set a time on his previous run, though it is not clear why.

The Mercedes head out in unison, both performing practice starts.

Leclerc begins his flying lap, the SF90 looking good. He goes quickest in S1, maintaining the pace in S2. At the line the youngster posts 29.569, to go quickest by 1.39s.

Elsewhere, Vettel can only manage a PB in S1, followed by another in S2. At the line he posts 29.738 to go second by 0.169, having been quickest in S3.

Ricciardo reports a cut in power as he left the pit exit.

Both Mercedes drivers have pitted without seeking to improve their times.

With 13 minutes remaining, the track falls silent, not a car to be seen.

Currently it's: Leclerc, Vettel, Verstappen, Hamilton, Bottas, Hulkenberg, Kvyat, Sainz, Norris and Perez.

The silence is broken by Norris, who heads out on a brand new set of softs. He is subsequently joined by Magnussen.

Magnussen improves to 8th with a 31.623, but it is unlikely that he will keep that position with that time.

Sainz goes fourth with a 30.965, with Norris posting 30.955 to go third moments later, despite a couple of mistakes.

Perez can only manage twelfth 2.069s off the pace, as Grosjean bangs in a 30.818 to take third from Norris.

Raikkonen goes ninth with a 31.333, but is demoted when Kvyat posts a 31.173.

Ricciardo posts a PB in S1, maintaining the pace in S2. The Australian finally crosses the line at 31.643 to go fifteenth, following a poor final sector, which must be disappointing.

Grosjean goes third and Hulkenberg fourth, as the midfield battle this afternoon and tomorrow threatens, once again, to be a thriller.

Verstappen fails to improve and remains 6th, while Bottas can only manage 30.389 which puts him third.

Hamilton posts a PB in S1, but he is already off the pace of the Ferraris. Indeed, he crosses the line at 30.334 to go third, albeit 0.765s off Leclerc's pace.

The session ends. Leclerc is quickest, ahead of Vettel, Hamilton, Bottas, Grosjean, Hulkenberg, Norris, Verstappen, Sainz and Kvyat.

Raikkonen is eleventh, ahead of Gasly, Magnussen, Stroll, Perez, Ricciardo, Albon, Giovinazzi, Russell and Kubica.

Despite what Mattia Binotto would have us believe, this is clearly not about engine modes.

Check out our Saturday gallery from Sakhir, here.