Reuters: Michael Schumacher entered his third decade in Formula One on top of the practice timesheets at his favourite Belgian Grand Prix on Friday before Red Bull's Mark Webber raised the pace in the afternoon.
Seven times world champion Schumacher made the most of the changeable conditions in the morning session, setting a time of one minute 54.355 seconds in his Mercedes on a dry track before the rain fell.
Webber, who was on pole at Spa last year and celebrates his 35th birthday on Saturday, then set the day's fastest lap of 1:50.321 in another rain-hit session after lunch, with Schumacher fading back to 11th.
Ferrari's Fernando Alonso and the McLaren pairing of Jenson Button and Lewis Hamilton followed the Australian with Red Bull's champion and runaway leader Sebastian Vettel back on 10th place.
With eight races left, Vettel has an 85 point lead over Webber and is 88 ahead of Hamilton.
Wearing a special golden helmet to mark the 20th anniversary of his grand prix debut at the circuit on Aug. 25, 1991, Schumacher and team mate Nico Rosberg were the only ones to lap in the dry in the morning.
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.
Further showers punctuated the afternoon.
Button, winner of the last race in Hungary before the summer break, was third fastest in 2:02.740 behind the Mercedes duo in the morning with Vettel fourth.
Lewis Hamilton, last year's race winner at Spa but recovering from a cold on his return, was behind Button in both sessions.
Brazilian Bruno Senna made his Renault debut as a replacement for ousted Nick Heidfeld but blotted his copybook by spinning into the tyre wall with just over half an hour to go.
Senna ended the first session in 23rd place, still only one behind Russian team mate Vitaly Petrov. The Brazilian improved to 17th in the afternoon while Petrov was caught out by the rain and ended up last on the timesheets.
The first 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.
Indian Karun Chandhok took the place of Finland's Heikki Kovalainen at Team Lotus for the first session.