Lewis Hamilton Back on Top in Second Practice of Russian Grand Prix

Lewis Hamilton was back in serious mode on Friday after bouncing back to top the times in second free practice for this weekend's Russian Grand Prix.

The defending three-time world champion, trailing his Mercedes team-mate Nico Rosberg by 36 points in the title race, made clear he was focused only on closing that gap and had no time for light banter.

Talking to reporters, he said he was reluctant to make any predictions after a slip-sliding day on the low-grip Sochi Autodrom circuit but hoped, above all, for a "clean weekend" without mishap.

Having seen Mercedes team-mate Nico Rosberg reel off three season-opening wins to take a commanding lead in this year's title race, Hamilton said he was intent on closing that gap and kick-starting his bid for a fourth crown.

After winning both of the two previous Russian events in 2014 and 2015, he is in line to complete a hat-trick.

"I hope so!" he said when it was suggested he had shown the speed to challenge for his first win in seven outings. "But most of all I am hoping for a clean weekend."

Hamilton was second-fastest in the opening session behind Rosberg, but responded with a determined display in the afternoon to outpace his rivals.

Four-time champion German Sebastian Vettel, who suffered an electrical failure and stopped out on track during the session, was second-fastest for Ferrari ahead of Rosberg, who was unable to find a clear lap and was third.

Hamilton rediscovered his mojo in the second session to clock a best lap in one minute and 37.583 seconds, more than six-tenths of a second quicker than nearest rival Vettel.

"Not too bad," was Hamilton's verdict. "It went quite well, but I did destroy one tyre when I had a spin. There is no grip out there on these tyres. It is not a very abrasive surface. It's so smooth."

'Solid start'

Rosberg was third in the second Mercedes, eight-tenths off Hamilton's pace, with Finn Kimi Raikkonen fourth in the second Ferrari.

"It's been a solid start to the weekend," said Rosberg. "It's difficult to get it right at this track, as there's only a small window where the tyres work perfectly and a lot of places where you can easily make mistakes.

"I didn't manage to hook up a full quick lap on the supersoft tyres, but aside from that, it was a good day.

"The car felt good on a quick lap this morning and again on the longer runs this afternoon, so that's very encouraging."

Vettel remained optimistic.

"We had an electrical problem," he said. "Obviously that's part of the electrical bits on the car! We don't know yet entirely but we'll have to see.

"I'm sure we can fix it, but we want to understand what happened. It's a bit of a shame because we're lacking a couple of laps, especially in the long runs and race trim, to see how competitive we are.

"I think that Kimi did homework for the team, so -- not too bad. Also I think here we know roughly what to expect. I think we can still learn a lot from what other people did."

Australian Daniel Ricciardo was fifth for Red Bull, having tested the team's latest cockpit safety device on his installation lap in the morning, with Finn Valtteri Bottas sixth for Williams.

Local hero Daniil Kvyat was seventh on his 'home' Sochi Autodrom circuit in the second Red Bull ahead of the two much improved McLaren Hondas of Jenson Button, who was eighth, and Fernando Alonso, who was 10th, the pair sandwiching Brazilian Felipe Massa of Williams in ninth spot.