F1: Rosberg quickest in first Spa practice

Mercedes was fastest in first practice for the 2014 Formula 1 Belgian Grand Prix, with Nico Rosberg outpacing Lewis Hamilton by 0.097sec.

As expected, Mercedes-engined cars dominated the top 10, with the 'works' cars trading quickest times in the final half-hour. Rosberg topped the times for the first half of the session with a 1m51.724s lap before Hamilton edged ahead, but Rosberg hit back by going another tenth of a second faster.

Hamilton's race engineer Peter Bonnington informed him that the time came from Rosberg being quicker through the chicane and picking up more mid-corner to exit speed at Pouhon. Both Mercedes then returned to the circuit in the final minutes but did not improve their times.

Ferrari arrived at Spa with a revised low-downforce aero package and proved to be the fastest non-Mercedes team. Fernando Alonso was especially impressive, third fastest and just two tenths off Rosberg's benchmark. Kimi Raikkonen, so often a Spa specialist, continued to fight his F14 T but finished fifth fastest, albeit a second slower than his teammate.

The Ferraris sandwiched the McLaren of fourth-placed Jenson Button, who survived a brief scare when his DRS stuck open. Button was a comfortable half second faster than teammate Kevin Magnussen.

Red Bull's Daniel Ricciardo was the only other top 10 runner without a Mercedes engine, closing the session in ninth place, behind Magnussen and the two Force Indias of Sergio Perez and Nico Hulkenberg.

Ricciardo's teammate Sebastian Vettel was two places adrift after an eventful session. He reported gearshift problems and ran off track at Pouhon, then ran just another handful of laps before returning to the garage with a temperature-related exhaust failure.

Valtteri Bottas was the only Williams driver to finish inside the top 10, seven tenths quicker than team-mate Felipe Massa.

While 1.595sec separated P1 from P10, the gap from fastest to slowest on the entire grid was a substantial 6.4sec, with the usual suspects propping up the order.

Alexander Rossi, who will not now drive in the grand prix after all, was over a second slower than Marussia teammate Jules Bianchi.

It only took F1 debutant Andre Lotterer 10 laps at the wheel of the newly upgraded Caterham to overhaul teammate Marcus Ericsson, who spun at La Source in response.