Overnight rain at the Shanghai International Circuit had left the track damp for the start of Friday morning's running and, aside from the usual installation laps, drivers opted to keep their powder dry in the garages and no lap time was duly set in the opening half an hour.

With the track slowly beginning to dry out, Red Bull's Mark Webber was the first driver to complete a timed lap and quickly worked his way down to a 1:39.558 before a further rain shower sent drivers scurrying back to the pit lane to trigger a further period of track inactivity.

After some drivers opted to test out the slippery track surface on intermediates, the track dried sufficiently again towards the end of the session for drivers to return to the slick tyres - which produced a flurry of activity at the top of the timesheet in the closing minutes.

First Mercedes' Michael Schumacher went fastest, and while Webber retaliated with a 1:38.977, the experienced pair were then joined in the late battle by Hamilton, the 2008 World Champion having put just three laps on the board up until then.

Hamilton was quickly on the pace too, completing two laps in the dying seconds to settle on a 1:37.106 as Nico Rosberg moved up to second in the other Mercedes, albeit a full second back.

Schumacher ended up third ahead of Sauber pair Sergio Perez - the star of the last round in Malaysia - and Kamui Kobayashi, with Webber slipping to sixth ahead of Red Bull team-mate Sebastian Vettel and the other McLaren of Jenson Button.

The McLaren duo had earlier clearly seen little use in risking their MP4-27 in the slippery conditions and duly completed just a handful of laps apiece prior to the closing 10 minutes, as championship leader Fernando Alonso opted for a similar policy in his Ferrari before returning to the track late on to set his best time on intermediates in 11th.

Hamilton, on pole for the first two races of 2012, is set to carry a five-place grid penalty into Saturday's qualifying session owing to a gearbox change - although McLaren chief Martin Whitmarsh offered up a small window of hope that his driver could yet avoid the costly grid drop.

The Briton told Sky Sports F1 that the team was running with the problematic unit, which has a crack in it, during first practice before making a final decision on whether it definitely needed to be replaced from Saturday onwards, although he admitted this was "99%" certain to happen.

Elsewhere, Lotus's Kimi Raikkonen finished at the foot of the timesheet after problems with his E20's DRS rear wing forced him to bring a slightly premature end to his session.

Practice 1 Results