F1: Rosberg in charge in first Sochi practice

Nico Rosberg continued his imperious Formula 1 form by topping the opening free practice session for the Russian Grand Prix.

The Mercedes driver outpaced team-mate Lewis Hamilton by 0.722 seconds, a surprisingly large advantage given both ran similar programmes using the same Pirelli tyre compounds.

The session also featured the track debut of Red Bull's aeroscreen cockpit protection concept, which Daniel Ricciardo used for an early installation lap.

During the first 40 minutes of the session, when drivers use one set of tires that cannot subsequently be run, Hamilton initially set the pace. While the track was quiet early on, both Mercedes reeled off eight-lap runs on one of their four sets of soft tires and traded top spot.

Hamilton looked to have prevailed despite losing the rear at Turn 2 and spinning onto the run-off area on his sixth lap, but given the low rates of tire wear and degradation at the Sochi circuit the battle continued into their second runs. That allowed Rosberg to hit back, setting a 1m39.097s on his 12th lap to secure top spot -just over two-tenths faster than Hamilton, who could not match that improvement.

Both Mercedes drivers bolted on super-softs for their second runs, with Hamilton unable to get near Rosberg, the latter only briefly having trouble when he ran across the run-off area at Turn 2. The German set his best time on his 22nd lap of the session and Hamilton had no answer for his pace, having only been able to improve on his soft-compound time by 0.458s.

Ferrari driver Sebastian Vettel prevailed in a tight battle for third ahead of team-mate Kimi Raikkonen and Williams driver Felipe Massa.

Both Ferrari drivers opted to run medium and then soft tires during the session, compared to the Mercedes strategy of soft then super-soft - meaning the duo were the only drivers on that rubber in the top nine.

Initially, Ricciardo held the position before Vettel jumped ahead of him. Raikkonen and then Massa, who did not post a time until there was just over 20 minutes remaining thanks to a clutch problem, then had stints in third before Vettel, who had suffered a brief spin at Turn 15 earlier in the session, set a best time 1.048s off Rosberg to secure the position.

Valtteri Bottas was seventh fastest behind Ricciardo in the second Williams, having been the closest challenger to the Mercedes drivers in the first 40 minutes. He was able only to find an improvement of less than a tenth of a second on his second set of super-softs, with both Williams drivers opting to use that compound in both parts of the session.

Daniil Kvyat was eighth in the second Red Bull, although he would have improved on his 1m40.218s time had he not spun at the penultimate corner while on a better lap.

Force India driver Sergio Perez, also running super-softs, was ninth with Carlos Sainz Jr 10th and the best non-Ferrari driver using softs.

Jenson Button was the quicker of the McLaren-Honda drivers, setting 11th fastest time on softs after recovering from a spin during the first 40 minutes of running. He ended up just over a tenth faster than Fernando Alonso.

Newly-appointed Renault development driver Sergey Sirotkin was 13th fastest on his second appearance in an F1 practice session, the first having come at the same venue for Sauber in 2014.

He drove Kevin Magnussen's car, with Alfonso Celis Jr the other non-race driver to appear and ending up slowest after Rio Haryanto was finally able to set a time with four minutes remaining to relegate him to bottom spot.

It was a challenging session for the Manor team, as Haryanto only joined in late on thanks to a technical problem, while Pascal Wehrlein's car needed a rapid floor change after picking up damage earlier on.

PRACTICE ONE TIMES

Originally on Autosport.com