German Nico Rosberg brushed off an early embarrassment to set the quickest time in the third and final practice session for the Chinese Grand Prix today.

The Williams driver had to be extricated from the gravel beside the entrance to the pit lane before coming back out to sweep around the track in one minute 36.133 seconds on a sunny morning at the Shanghai International Circuit.

Italian Jarno Trulli was second quickest for Toyota in 1.36.272 ahead of Britain's world champion Lewis Hamilton (1.36.330), who had another encouraging morning in his McLaren. Jenson Button, who has won the first two races of the season, was fourth quickest in 1.36.463 but the Briton will be reassured by the fact that all the times were considerably slower than the 1.35.679 he set in yesterday's practice.

The Brawn GP driver remains a clear favourite to claim a third successive pole position of the season in qualifying, which takes place later on today.

Rosberg, who set the second quickest time behind Button yesterday, had a start to the day to forget.

Less than three minutes into the one-hour session, the 23-year-old slid off the asphalt and it required a crane to lift his Williams from the gravel.

The incident occurred just metres away from where Hamilton's world title challenge foundered in similar circumstances during the 2007 race in Shanghai.