Sebastian Vettel led championship leader Mark Webber in a dominant Red Bull one-two in both practice sessions for the Japanese Grand Prix on Friday.

While they flaunted an advantage of more than half a second over their title rivals, McLaren's Lewis Hamilton could only watch impotently from the sidelines after crashing in the morning.

When the 2008 Formula One champion did get back on track with eight minutes of the second session remaining, the Briton was able to complete just six laps with the 13th fastest time of the afternoon.

The 25-year-old, determined to throw caution aside after three retirements in four races dropped him to third place and 20 points behind Webber, had completed nine laps before running wide at the Degner double right-hander and smacking the tire wall.

The car came to a halt under the bridge with the front left wheel hanging limply.

Hamilton stepped out, shaking his head, but keeping his yellow helmet on to hide his undoubted fury at having to sit out the remaining 45 minutes.

With heavy rain forecast for Saturday, the McLaren title contender knew he had blown his chance of getting a feel for the new bits his team had brought to the race in an all-out push to catch up with Red Bull.

"I was probably pushing too hard, too early. I don't know," he said of his third crash in three races.

"They say bad things come in threes so hopefully that's the case, it's over and done with."

Vettel quickest

The Red Bull drivers, teammates and fierce rivals, had no such problems with their cars powering around the flowing figure of eight circuit as if on rails.

Vettel, last year's winner at the Honda-owned circuit and fourth in the title battle, set a best time of one minute, 32.585 seconds on a dry track in the morning and then, with the sun high in the sky, bettered it after lunch with a 1:31.465.

"The car was reliable and I had a good feeling," Vettel said. "The forecast suggests rain but there's no reason why we shouldn't be competitive in the wet."

Australian Webber, who is 11 points clear of Ferrari's Fernando Alonso with four races left, was 0.048 and 0.395 slower.

"We couldn't have asked for much more," he said. "We had faultless running and got a lot of mileage. The team put the cars together well and we had a smooth day."

Renault's Robert Kubica was the best of the rest in both sessions, 0.544 slower in the first and an even more demoralizing 0.735 off the pace in the second.

McLaren, which has vowed to throw everything 'including the kitchen sink' at its car in the remaining races, had world champion Jenson Button sixth fastest in the afternoon.

Despite his accident, Hamilton was fifth quickest in first practice. Button also went wide at Degner in that session, but avoided Hamilton's fate.

Alonso, the double world champion who has won the past two races, ended the day fourth fastest with Brazilian teammate Felipe Massa fifth.

"It's only Friday, so the times today do not really mean much," said the Spaniard. "In theory, Red Bull look unbeatable here ...(but) there were various races where come Sunday, they were beaten."