Silverstone: Nico Rosberg topped the times ahead of Mercedes teammate and Formula One championship rival Lewis Hamilton in the first practice for the British Grand Prix on Friday.
Rosberg, who leads the title race ahead of Hamilton by 29 points, clocked an early best lap of 1 minute, 35.424 seconds, to take the initiative ahead of Hamilton, who wound up seven-tenths of a second slower on a wind-swept day. (Also read: Hamilton targets home win to boost title bid)
Two-time champion Fernando Alonso of Ferrari was third, followed by Red Bull's Daniel Ricciardo, 2007 champion Kimi Raikkonen in the second Ferrari, and Sebastian Vettel in the second Red Bull. (Read: Alonso warns Ferrari to expect difficult times)
Jenson Button, the 2009 F1 champion, was seventh for McLaren. The top 10 was rounded out by the two Toro Rossos of Russian rookie Daniil Kvyat and Frenchman Jean-Eric Vergne, and Danish rookie Kevin Magnussen in the second McLaren.
Susie Wolff became the first woman to take part in a grand prix weekend for 22 years, but lasted only three laps before her engine failed - and only a few minutes later her Williams teammate Felipe Massa crashed out of the session.
"It was a really tough day, but that's Formula One sometimes," Wolff said. "We had an oil pressure problem which cut the engines - the guys are looking at getting it fixed for free practice two."