Ahead of today's sole practice session the air temperature is 23.3 degrees C, while the track temperature is 31.2 degrees C. Though there remains plenty of cloud, it remains bright.

Though Sebastian Vettel claimed there was "catching up to do" yesterday, Valtteri Bottas is under the impression Ferrari has something up its sleeve... the answer to be revealed over the next few hours.

Though the German set the pace in FP1, he was 0.543s off the pace in FP2. Vettel put the problems down to tyres and traffic.

With both Red Bulls, and the Toro Rossos and Fernando Alonso, consigned to the back of the grid tomorrow, Mercedes and Ferrari know what they have to do today, while also knowing that they won't be needing to fend off Max Verstappen early tomorrow afternoon.

Though Ferrari has brought an upgrade, including a new front wing, it is the less radical upgrade from Mercedes, including a new rear wing, which appears to be achieving the best results. Thus far.

Like Vettel, mist drivers struggled for grip, the 'greenness' of the Sochi track being one of the main issues. Indeed, over the course of the two sessions there were spins and excursions but nothing serious.

As ever, the midfield is where it's really happening, and on the evidence thus far, the Force India, Renault, Haas, Toro Rosso and Sauber duos should be involved in some decent scraps tomorrow.

That said, Toro Rosso has opted to revert to its older spec engine for the remainder of the weekend, no doubt saving the upgraded unit for Suzuka.

McLaren and Williams, on the other hand, who were both well off the pace, will be merely bit-part players.

The qualifying sims should be interesting late in the session, the hypersofts prone to rapid degradation.

Alonso heads the queue at the end of the pitlane, and leads Leclerc, Verstappen, Hartley and Ericsson out on to the Sochi track. The cars feature a mix of hypersofts and ultras.

Alonso posts the first time of the day, the Spaniard crossing the line at 1:37.713. Shortly after, Sirotkin posts 37.704.

As Alonso improves to 37.466, on-board with Stroll shows that Canadian having a horrendous time in the Williams, really struggling keep the car on the black stuff.

Once again, the McLaren pair are giving one another tows. With Alonso destined for the back of the grid, a tow from the Spaniard is Vandoorne's best chance of a decent qualifying time.

Raikkonen goes quickest with a 35.074 as Vettel begins his flying lap. The German subsequently posts 33.859, bettering his best from yesterday.

Raikkonen improves to 34.343, almost half-a-second off his teammate's best. Both are on fresh hypers.

Also on fresh hypersofts, Bottas splits the Ferraris with a 33.941, just 0.082s off Vettel's pace-setting time.

No sooner has Verstappen headed out on fresh hypers than the Red Bull driver pits again.

Hartley goes fourth with a 36.599, the Kiwi on notice that he has to beat Pierre Gasly in the remaining races if he is to retain his seat for 2019.

Bottas goes quickest with a 33.809, as Ericsson runs wide at T7.

On his first flying lap, Hamilton goes quickest in S1, losing a little pace in S2. At the line he posts 33.919 to go third, losing out courtesy of that middle sector.

As Bottas looks set to improve, replay shows Hamilton running a little wide in S2 on that previous lap.

Leclerc goes fifth (35.231), ahead of Ocon, Gasly, Ericsson and Hartley.

Traffic means that despite a strong opening sector, Bottas is unable to improve.

"Check everything is okay," says Grosjean, "I suddenly lose the front end big style."

Ricciardo goes fifth with a 35.135 as teammate Verstappen heads out again.

Hamilton goes quickest with a 33.664, the Briton now 0.195s quicker than title rival Vettel.

As Grosjean almost trips up over Vandoorne, Verstappen, seeking clear air, runs very wide in a bid to allow Gasly through.

It's a peculiar lap from Verstappen, who runs wide at least twice on his lap, eventually aborting, as he and the Renault pair remain the only drivers still to post a time.

Another improvement from Hamilton who ups the ante with a 33.496. Nonetheless, the Briton, after asking about his middle sector, is informed that Turns 7 and 8 are the turns he needs to work on.

With 27:00 remaining, Sainz posts 36.124 to go twelfth, leaving Verstappen and Hulkenberg as the only drivers still to post a time.

In the Ferrari garage, both cars are up on their stands, with work on the rear suspension appearing to be the focus of attention.

Grosjean complains about his earlier incident with Vandoorne, while Ocon claims Verstappen was "totally" slow on the racing line.

Verstappen finally posts a time as does Hulkenberg, the Red Bull driver going 9th with a 35.271 while the German posts 35.401 to go 10th.

"I think we've got a problem with the front suspension broke," reports Grosjean, "the car is not reacting normally."

"I box, this is useless," snarls Verstappen, the Dutchman clearly unhappy.

As the qualifying sims get underway, Alonso is told he will have the track to himself... in fact he won't, as Vettel and Gasly sneak out to join him.

Vettel can only manage a PB in S1, not helped by a mistake at T4 and another at T7. He clearly doesn't have the grip he needs and aborts the lap.

Bottas and Hamilton head out.

With those grid penalties, the Bulls and Toro Rossos will most likely be looking ahead to tomorrow rather than qualifying.

Bottas goes quickest with a 33.321 despite only being quickest in S1.

As Hamilton goes quickest in S1, Vettel aborts another lap. Elsewhere, Raikkonen heads out.

Asked if he wants another flyer, Vettel responds: "I'm still thinking about it."

Quickest in S3 also, Hamilton cross the line at 33.067 to go quickest, leaving 0.792 of clear air to title rival Vettel.

PBs in all three sectors see Raikkonen leapfrog his Ferrari teammate, though the Finn is 0.784s off Hamilton's pace.

Perez is currently fifth, ahead of Ricciardo, Ocon and Verstappen, until all are demoted when Leclerc posts 34.771 to go fifth.

Now Vettel goes quickest in S1, however on-board shows his front-left to be blistered. He loses pace in S2 finally crossing the line at 33.667 to go third, the German losing a heap of time in S3 on his (six lap old) tyres.

Ever the rebel, Alonso is the only driver not on hypers, the Spaniard sticking with ultrasofts.

A 33.937 sees Verstappen improve to fifth as Raikkonen also improves but remains fourth.

Check out our Saturday gallery from Sochi, here.