Down-on-his-luck Didier Defago emerged from the shadows of powerful Swiss ski teammates to win his country's first men's Olympic downhill title in 22 years.

It was the highlight of Olympic action that featured a second US triumph at the expense of a Canadian pace-setter in snowboard cross and the return to the podium of a 32-year-old cross country skier who earlier quit the sport because she was so happy being a new mother.

Korea's Mo Tae-bum, racing on his 21st birthday, won the men's 500 metres speedskating in a contest interrupted for more than an hour after problems with the battery-powered machine that resurfaces the ice.

But it was the men's downhill that attracted most attention under a blessedly clear Whistler sky. The race was postponed from Saturday because of rain and fog.

Defago, hampered by a thumb injury this season, had faced problems even making Swiss team. He reached the pinnacle of men's skiing at age 32 and stunned pre-race favourites, Didier Cuche and Carlo Janka.

'The fact that I needed to qualify made me angry, in a way, but in the end, it may have helped because I had to be competitive from the training runs,' said the quiet family man from a Swiss Alpine village.

Defago, the 'other Didier', became the first Swiss to win a men's Olympic downhill gold since 1988, when Pirmin Zurbriggen won on Canadian snow at Calgary.

The showcase Alpine event was also a tale of Olympic redemption for another, more famous, 32-year-old, after a failure to medal in 2006.

American skiing's wild child Bode Miller took the bronze medal in a much anticipated comeback, finishing close behind silver medallist, Aksel Lund Svindal from Norway.

For host nation Canada, a disastrous downhill, coupled with a last-seconds loss to the Americans in snowboard cross, brought locals back to earth their first home-turf Olympic gold on Sunday.

US boarder Seth Wescott soared past Canada's Mike Robertson at the end of the hot-dog four-man race to nab the gold, just a few hundred metres from where Alex Bilodeau made Canadian medal history on the moguls the day before.

It was the second gold for the United States, but Switzerland leads the medals table with three golds after victories in men's 15km cross country and downhill.

Miller, who failed to medal in Turin four years ago and courted controversy with past partying, flirted with gold before Svindal and Defago pushed him down the podium.

'I was really nervous this morning,' said the man who once owned American skiing. 'Once I got going, I felt really, really solid.'

Americans are hoping for another turnaround from Turin in Lindsey Vonn, favourite for Wednesday's women's downhill.

Speaking after the racers' first full training run, Vonn said she was shocked by the bumpy, jarring course, a route that might bode poorly for a shin injury on the mend. In a Facebook update, she said the shin was 'really sore again'.

Other comeback stories included Kristina Smigun, the Estonian cross country skier who came out of retirement after having a baby and won the silver medal in the women's 10km freestyle.

In Canada's zeal to 'own the podium' at the Vancouver Olympics, it was as if Sunday giveth and Monday taketh away.

Vancouver ski ace Manuel Osborne-Paradis, a downhill favourite who hoped to carry on Canada's gold momentum, lost precious ground on the lower part of the Whistler course and ended back in the pack, and Jeremy Wotherspoon ended well outside the medals in the speedskating.

That was in sobering contrast to the glory of compatriot Bilodeau, the 22-year-old mogul master who put an end to talk of the so-called Canadian medal 'curse'.

Canada hosted Olympic Games in Montreal in 1976 and Calgary in 1988, but won no golds at either games.

Bilodeau's win brought much needed joy to a Games that endured a difficult first few days after the death of a Georgian luger in training on Friday.

Games organisers held a memorial service for Nodar Kumaritashvili, 21, on Monday before his body was flown home, while women sliders took their first competition runs down a shortened track.

Canadian attention will now focus on the start of the men's ice hockey competition on Tuesday, with Canada paired against Norway.

The Canadian women have got off to a storming start, with a 10-1 win against Switzerland on Monday that followed their record breaking 18-0 rout of Slovakia.