Alonso wary of Red Bull's speed

Red Bull's Sebastian Vettel and Mark Webber were quickest in Friday's practice sessions, with Alonso second fastest in the afternoon.

The Ferrari driver, however, was nearly four tenths of a second off Webber's time.

Although he was pleased with his day's work, Alonso conceded more pace was needed to fight with Red Bull.

"It's been a pretty good Friday to confirm all the updates that we were bringing, which worked well," Alonso told Spanish reporters after practice.

"But we know we have to improve the car tonight. It's not enough at the moment.

"The Red Bull are a lot quicker than us at the moment, so we'll try to get as close as possible tomorrow to have a good Saturday."

The Spaniard is also expecting McLaren to be close to Ferrari in tomorrow's grid-deciding session, despite the British team enduring a difficult day today.

"No, I think it will be very close tomorrow," he said. "We saw at Valencia too that McLaren on Friday was far back in the second session and then on Saturday Hamilton was in front of us and Button right behind.

"I think tomorrow will be similar, with three or four teams fighting for positions and let's hope we are a bit in front of them."