SILVERSTONE, England — Mercedes driver Nico Rosberg showed once again he has the car to challenge the top drivers, clocking the fastest lap in practice Friday at the rain-soaked British Grand Prix ahead of Red Bull drivers Mark Webber and Sebastian Vettel.

Rosberg, who won the Monaco GP and was on pole at the Spanish GP, was 0.299 seconds faster than Webber. It was the first time the Australian had been on track since surprising his team on Thursday by announcing he would be leaving Formula One at the end of the season to race sports cars.

"On one lap the car is still quick, so qualifying should be OK," Rosberg said. "But the question mark is our race speed. We practiced the race speed today and it felt decent so far. But it could be a completely different picture on Sunday as the weather should be a lot warmer, so we don't know where we are right now compared to the others. I'm still quite confident that we can have a good weekend."

Vettel, the three-time defending champion, was 0.432 seconds behind as he looks to extend his lead atop the drivers' championship.

The German has a 36-point lead over Ferrari's Fernando Alonso with 12 races remaining. Lotus driver Raikkonen is another eight points back in third and Mercedes driver Lewis Hamilton is fourth.

"I think overall we can be pretty happy. It was a good day," Vettel said. "Obviously it was important to get some laps in the dry as we expect dry conditions on Sunday. Now we need to have a look at what we can improve, have a look what the others did and then we'll know a little bit more for tomorrow."

Hamilton was the closest among Vettel's rivals, coming in fifth fastest while Alonso settled for 10th and Raikkonen 13th. Hamilton, the 2008 champion, called it "quite a challenging day."

"I'm struggling a little with the balance of my car so there's some work to do overnight to get us into shape for qualifying," Hamilton said. "We haven't quite got it hooked up yet and you can really tell that on this circuit."

On a rainy day at Silverstone, teams were forced to get much of their track time in on the second session after rain washed out most of the first practice. The track was mostly dry but it still caused plenty of problems for Alonso's teammate, Felipe Massa.

Massa spun and crashed into a wall on Turn 15, the latest setback for the Brazilian who has had crashes in two earlier races. He crashed in practice and the race at Monaco and then in qualifying at the Canadian GP.

"I am very disappointed about what happened today as the accident cost me valuable time, especially in terms of getting an understanding of the tire behavior here at Silverstone," Massa said. "At the exit of the corner, I found myself on a piece of track that was still very damp and I lost control of the car. Luckily, the car only suffered slight front end damage and tomorrow we will comfortably be able to pick up where we left off with the work."

Silverstone also held a minute of silence Friday for marshal Mark Robinson, who was killed in a track-side accident at the Canadian Grand Prix.

In the first session, Toro Rosso's Daniel Ricciardo set the fastest lap of 1:54.249 followed by Sauber's Nico Hulkenberg, who was 0.784 seconds off the pace. Williams driver Pastor Maldonado was third fastest.

Fans in the packed grand stand were left frustrated, since the track remained empty for most of the 90-minute session while it rained on Silverstone. Expecting dryer conditions this weekend, teams gambled they would learn little from a wet track.

The teams defended the decision, citing safety concerns. But many did apologize for letting down fans at a circuit that often draws some of the biggest and boisterous crowds in Formula One

"I'm sorry for the fans who packed the circuit today, who did not get to see the show they were expecting because of the rain," Ferrari's Pat Fry said. "In the morning, track conditions were extremely difficult and with the few sets of tires available, we preferred to stay in the pits, as did almost all the other teams."

Red Bull's Christian Horner joked that Silverstone might need to follow Wimbledon's example and "invest in a roof."

"From a team perspective, we want to be out there because you want to learn and we're limited on track testing as it is but unfortunately you can't fully predict the British summer," he said. "We sent Sebastian out early on to have a look and he said it was right on the edge in terms of aquaplaning and with the limitation on parts and so on, we had to make a decision to say OK, we need to wait a bit later until the circuit conditions improve."

Half the drivers went out in the session, though Hamilton was the only title contender to set a lap time. Several drivers struggled with the wet track including Caterham's Charles Pic, who slid into a wall. He was unhurt.