SILVERSTONE (England) - GERMAN Sebastian Vettel topped the times for Red Bull in Friday morning's opening free practice for Sunday's British Grand Prix, narrowly outpacing his Australian team-mate Mark Webber at the top of the time-sheets.

The outcome of the first 90 minutes' action on a cold and breezy day at the high-speed Silverstone track endorsed the potential of the team this weekend.

After Webber had dominated most of the session, Vettel managed to outpace him in the final seconds with a best lap of 1min 19.400sec, an advantage of just two-tenths of a second. Button was a further six-tenths of a second behind.

They wound up as the top two ahead of the two Brawn GP men championship leader Briton Jenson Button and his team-mate Brazilian Rubens Barrichello.

Behind the top four, two-times champion Spaniard Fernando Alonso delivered a fast set of laps for Renault to clock the fifth best time ahead of Brazilian Felipe Massa in the leading Ferrari.

Italian Jarno Trulli was seventh for Toyota ahead of defending world champion Briton Lewis Hamilton of McLaren Mercedes and German Nico Rosberg in a Williams with Italian Giancarlo Fisichella 10th for Force India.

The pace of the Red Bull cars followed major revisions for this weekend's race.

The team had moved both axles to change the weight distribution and introduced a new diffuser - a so-called triple-decker this time - in a bid to increase their down-force and bring in a new nose and engine cover. -- AFP