Red Bull's Formula One world champion Sebastian Vettel put down a marker for a possible fifth win in a row by dominating both practice sessions for the Chinese Grand Prix on Friday.

The 23-year-old German, chasing his third victory of the season, lapped the monumental Shanghai circuit with a best time of one minute, 37.688 seconds on a smoggy afternoon with few spectators in attendance.

McLaren's Lewis Hamilton was 0.166 adrift, a big improvement on the morning that saw him more than two seconds off the Red Bulls' pace.

Vettel's Australian team mate Mark Webber had been second fastest in the morning but was only 10th after the break.

Both Red Bulls looked in a class of their own after the garages opened for first practice at the track outside Shanghai, with Hamilton third but a massive 2.106 seconds slower.

Jenson Button, the 2009 world champion who won last year's race, was 2.201 off the pacesetting best in the morning after his McLaren suffered KERS problems but bounced back to end the day just 0.247 off Vettel's best.

Renault's Nick Heidfeld, buoyed by third place in Malaysia last Sunday, was consistent enough to crunch his car into the tyre barriers in both sessions but was fifth fastest in the morning despite completing only five laps.

Ferrari's Brazilian Felipe Massa was sixth in both, with the team carrying out aerodynamic tests to try to get to the bottom of their lack of pace, while Spaniard Fernando Alonso was 12th and 14th after being sidelined by hydraulic problems.

Team principal Stefano Domenicali, back at the helm following a flying visit home to Maranello for a post-race inquest after Malaysia, will be hoping for a far better performance on Sunday.

Seven-times champion Michael Schumacher is returning to the scene of his last win and podium finish with Ferrari in 2006 and ended the day an encouraging fifth for Mercedes.

Force India's British rookie Paul di Resta sat out the second session after his Mercedes-powered car suffered a fuel pressure problem.