tel continues to dominate

Sebastian Vettel finished top of the timesheets for the third practice session in a row as the world champion continued to boss his rivals ahead of Sunday's Chinese Grand Prix.

The German's best time of one minute 34.968 seconds maintained his perfect form in Shanghai after finishing top of both free practice sessions on Friday.

McLaren were again Vettel's nearest challengers, but try as they might Jenson Button and Lewis Hamilton again found themselves unable to pull out those few tenths of a second that would usurp their rival.

Button got the better of Hamilton, who went off at turn one while pushing too hard towards the end of the session, to take second place, 0.208secs down on Vettel, while his team-mate took third, another two tenths back.

There was more woe for Vettel's team-mate, however, the hapless Mark Webber suffering a troubled session to finish down in 15th.

The Australian has failed to match the form which has brought Vettel two wins out of two this season, finishing fifth in Australia and fourth in Malaysia last weekend.

Webber had hoped for better this weekend, but an apparent issue with his car's KERS turbo-boost - the same problem which affected his race in Malaysia - limited him to just one flying lap. He walked disconsolately away from his car with four minutes of the session remaining, and his mechanics have a job on their hands to remedy the problem in time for qualifying later on Saturday.

The session was run in much cooler temperatures and without the smog which was so much a feature of Friday's action.