The two superstars of American winter sports won an Olympic gold medal each on Wednesday - snowboarder Shaun White in the halfpipe and Alpine skier Lindsey Vonn in the women's downhill.

White, 23, was peerless throughout the competition but waited until his title had been confirmed by his first run before he performed the much talked-about double McTwist 1260, which requires him to flip twice while completing three and a half spins, on his second.

That earned him an extraordinary 48.4 points from the five-judge panel, just 1.6 off the maximum, and 3.4 more than silver-medallist Peetu Piiroinen.

The Finn produced a startling second run himself to displace American Scott Lago into the bronze medal position.

But it was not good enough to get close to White who was the only finalist to get nine-plus scores from all five judges twice.

The first run from White, who has his own private halfpipe on which to practice in Colorado, was good enough to beat everyone else as back-to-back 1080s earned him 46.8 from the wowed judges.

'I just felt like I didn't come all the way to Vancouver not to pull out the big guns,' White said of his innovative second run. 'I put down the tricks I've worked so hard on.'

Vonn lived up to her billing as red hot favourite for the women's downhill title by sweeping to a gold medal triumph at Whistler Creekside.

The double world champion American, hampered by a shin injury in the build-up to the race, showed no ill effects as she posted a time of one minute 44.19 seconds that was never under threat from her rivals.

Vonn, who crashed in training at the Turin Olympics four years ago but returned the following day and finished eighth, savoured her gold medal breakthrough.

'It's the best day of my life,' she said. 'It's awesome. It is a really bumpy challenging course and I nearly lost it at the top but I just kept it going and I am just so happy that I made it down.'

There was more American success when eight-time speed skating world champion Shani Davis defended his Olympic title in the 1000 metres at the Richmond Olympic Oval, finishing in one minute, 8.94 seconds.

That was enough to edge out South Korean 500m champion Mo Tae-Bum by 0.18 seconds. Mo took silver ahead of Chad Hendick of the United States, who was 0.2secs further back.

At the short track, Meng Wang of China defended her title in the women's 500m but she had to beat two Canadians at a partisan Pacific Coliseum.

Wang silenced the home fans by edging Marianne St Gelais into second place while the other home favourite, Jessica Gregg, left with nothing as Italy's Arianna Fontana clinched the bronze medal.

Two pairs of brothers took gold and silver in the double luge at Whistler Sliding Center.

Austria's Linger brothers - Andreas and Wolfgang - were the winners, just edging out Andre and Juris Sics of Latvia.

German duo Patric Leitner and Alexander Resch were the bronze-medallists.

In the cross country skiing, Russia enjoyed a one-two in the men's individual sprint classic, Nikita Kriukov taking gold in three minutes, 36.3 seconds in a photo finish with compatriot Alexander Panzhinskiy at the Whistler Olympic Park.

The result represents an impressive improvement for the duo. Kriukov's best result at World Cup level was a third place finish in November 2009 while Panzhinskiy has managed no better than fifth.

Petter Northug of Norway won bronze.

Norway's Marit Bjorgen won the women's individual sprint classic, taking a gold medal to go with the silver she won in the same event four years ago.

The 29-year-old finished in a time of three minutes 39.2 seconds.
She just edged out Justyna Kowalczyk of Poland, who earned a silver ahead of Petra Majdic of Slovenia.