Michael Schumacher tops timesheets at wet Spa

The seven times world champion made the most of the changeable conditions, setting a best lap of one minute 54.355 seconds in his Mercedes on a dry track before the rain fell. Wearing a special golden helmet to mark the 20th anniversary of his grand prix debut at the circuit on August 25, 1991, Schumacher and team mate Nico Rosberg were the only ones to set a time in the dry.

A heavy shower hit the circuit in the Ardennes forests with only 10 minutes gone and drivers completed the session on wet specification tyres with little action for much of it. Behind the Mercedes duo, McLaren's Jenson Button, winner of the last race in Hungary before the summer break -- was third fastest in 2:02.740 ahead of Red Bull's championship leader Sebastian Vettel.

McLaren's Lewis Hamilton, last year's race winner at Spa but nursing a cold on his return, was fifth fastest.Brazilian Bruno Senna made his Renault debut as a replacement for ousted Nick Heidfeld at Renault but blotted his copybook by spinning into the tyre wall with just over half an hour to go. Senna ended the session in 23rd place, still only one behind Russian team mate Vitaly Petrov.

The session was halted for nine minutes when British rookie Paul di Resta followed Senna into the barriers with 16 minutes remaining and the rescue crane still busy removing Senna's damaged Renault. With eight races left, Vettel has an 85 point lead over team mate Mark Webber. The Australian, who celebrates his 35th birthday Saturday, was 16th.