Sebastian Vettel goes off at Turn Two, but there's plenty of run-off and he's soon back on track. The German isn't the first to run wide there, where drivers have to brake heavily as speeds drop to 100kph.

Mercedes start to stretch their legs, with Nico Rosberg going second with a 1:42.670, just over a tenth slower than pace-setter Jenson Button, with Lewis Hamilton slotting into third.

Valtteri Bottas' session is over. Why? Because a tyre blanket has failed, damaging the Finn's next set of tyres according to the team.

The McLarens of Jenson Button, the current pace-setter, and Kevin Magnussen are still in the garage as the team carry out planned set-up changes on both cars.

Four-time world champion Sebastian Vettel improves to the seventh fastest time (1:44.809) as the German clocks up the laps on a largely empty track.

Mercedes on Twitter:, external Bit of vibration on the brakes for @LewisHamilton earlier so a few tweaks needed. All ready to rock again.

The sight of Kimi Raikkonen's Ferrari up on the jacks in the garage during practice has been a common occurrence of late and it's more of the same this weekend.

The Finn pulled into the pits with smoking front brakes, which is a bit of a pain for the 2007 world champion who told the BBC last weekend that he relies on having a responsive front end of the car.

Image source, Getty Images

It's a big weekend for Daniil Kvyat, 20, who will be the only Russian on the grid on Sunday for his nation's inaugural F1 race weekend. That occasion deserves a special helmet, which features the slogan "Sochi 2014" on the chin.

Andrew Benson
Chief F1 writer in Sochi

"Romain Grosjean came up with a nice little anecdote on Thursday. He said he was looking forward to racing in Russia not only because it was a new race, but because it was around a former Olympic Park.

"It turns out his grandfather Fernand Grosjean was a world-class skier, who competed in the Winter Olympics for Switzerland in 1948 and '52, finishing eighth and 11th. 'Not bad," Romain said, revealing that skiing was his first love. 'I should have been a skier. That was my first love. Racing came later.'"

Red Bull boss Christian Horner tells Ben Edwards that Daniil Kvyat sat in the car yesterday as he begins preparations to set up from Toro Rosso to the senior squad.

"The way Daniil has developed during the season has been very impressive," says Horner.

Jeffrey Nederlof:, external I have a feeling that this track will stay on the calendar for more than three years compared to Korea and India.

Mark Ellison:, external Hmm, Sochi looks like a combination of Valencia and Abu Dhabi. And not in a good way.

Get involved via the #bbcf1 hashtag, 81111 on the text (UK only) or by leaving a comment on the BBC Sport Facebook page.

Interesting decision from Caterham's Roberto Merhi and Marcus Ericsson, who decided to do just one installation lap apiece in the first 30 minutes.

Team boss Manfredo Ravetto says it s because they are waiting for the track to rubber in, according to BBC F1 pit-lane reporter Tom Clarkson.

However, as this is a new track, you'd have thought the team and drivers would want to get out there and learn as much as they can, especially as this team are still chase their first F1 points.

It's all gone quiet as drivers head back into the pits because they've got to hand back the extra set of tyres they are given for use only in the first 30 minutes of the session.

1) But 2) Bot 3) Alo 40 Kvy 5) Ros 6) Mag 7) Ver 8) Per 9) Mas 10) Ham

Jenson Button goes quickest with a 1:42.507, one second clear of the rest of the field. Valtteri Bottas is his closest challenger, with Fernando Alonso third and Russian Daniil Kvyat fourth.

Andrew Benson
Chief F1 writer in Sochi

"Jules Bianchi's accident has revived discussion about the wisdom of closed cockpits in F1, or at least some form of forward head protection. Many of the drivers admit to being conflicted on the issue. Fernando Alonso was the man who had been most been at risk of being hurt in an incident such as this in recent years, when Romain Grosjean's Lotus flew over his car's nose in Spa two years ago.

"'Even in my case, in 2012 at Spa, I probably could have died there in corner one if it had been 10cm closer to my head. If the technology is there available and there is the possibility I would not exclude [closed cockpits] for sure. I probably tend to agree we should at least check and try or test the idea.'

"Sebastian Vettel added: 'I've got sort of mixed feelings. For F1 cars since the beginning of F1, and open-wheel racing, [open cockpits] is one of the things that is very special. On the other hand, as Fernando has touched on, there are a lot of reasons to look at closed cockpits for the future.'"

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Williams' Felipe Massa locks up a couple of times as he clocks a 1:45.419 which is good enough for eighth quickest at the moment.

Here's a shot of Lewis Hamilton's helmet for this weekend, which bears the hashtag #ForzaJules in support of Jules Bianchi. Read more from Hamilton in his latest BBC Sport column, available on the F1 pages.

Lewis Hamilton is back in the pits as the team investigate the vibration the Briton reported as he set his first few timed laps. Meanwhile, out on track, Fernando Alonso goes quickest with a 1:44.226.

1) Alo 2) Ros 3) Ham 4) Bot 5) But 6) Ver 7) Kvy 8) Ric 9) Mas 10) Vet

Nico Rosberg sweeps back to the top of the timesheets, the German clocking a 1:44.707. Fernando Alonso pops into third ahead of Daniel Ricciardo and Jean-Eric Vergne.