Mark Webber set himself up for a memorable 35th birthday on Saturday when he topped the times for Red Bull in Friday afternoon's second free practice session for this weekend's Belgian Grand Prix. The Australian, who is the only man among the leading drivers still without a win this year, clocked a fastest time of one minute and 50.321 seconds to outstrip his nearest rival Fernando Alonso of Ferrari by one-tenth of a second. "The weather was a little bit up and down today -- we got some dry running in, but only around four laps, two laps on the soft tyre and two on the medium," said Webber. "Otherwise we were just doing general housekeeping, looking at ride heights, brake balance and all that stuff before we get the car to the limit. We need to get out there and get the mileage in, but on the other side of the coin we need to save tyres for Saturday and Sunday. "The kerbs are the hardest thing here when it’s wet, it makes the white lines like ice and it's very easy to make a mistake." Two-time champion Alonso was one of several men to trade fastest laps with Webber along with his Red Bull team-mate and defending champion Sebastian Vettel and McLaren's Jenson Button. "We had a little bit of running in the dry," said Vettel, who won five of the opening six races, but has won only one of the last five and none of the last three. "On the front wing we got a decent result on that, but that was the only run we had in dry conditions." Seven-times champion Michael Schumacher had topped the times in the morning's opening session for Mercedes, marking the 20th anniversary of his Formula One debut with a flourish. But in the afternoon he wad down in 11th, five places behind his Mercedes team-mate compatriot Nico Rosberg, while Vettel wound up 10th. "It was a special feeling to be out on track today for the first practice sessions of this anniversary weekend here in Spa," said Schumacher. "A lot of things have changed here in the past 20 years, but the weather certainly hasn't." Button was third ahead of his McLaren team-mate and fellow-Briton Lewis Hamilton, the 2009 and 2008 champions maintaining impressive progress on a day of near-incessant heavy rain at the majestic Spa-Francorchamps circuit in the sprawling pine forests of the Belgian Ardennes. Alonso's Ferrari team-mate Felipe Massa, a fortunate winner of last year's race, was fifth ahead of Rosberg, Sergio Perez of Sauber and Nico Hulkenberg, who revelled in a rare opportunity to have a day's running for the Force India team. Briton Paul Di Resta was ninth in the second Force India car ahead of Vettel and Schumacher. Few fans at the track can have enjoyed their day other than the true die-hards as Spa's infamous and capricious micro-climate delivered a deluge that forced many to hide under canvas in the campsites.