(CNN) -- It was first blood to the United States in their ice hockey rivalry with hosts Canada with a stunning 5-3 victory in their much-vaunted clash on Sunday night.
Ice hockey is Canada's national sport and they went into the Winter Games on home ice as pre-tournament favorites, but a youthful U.S squad upset the odds.
Both teams had already qualified from the preliminary round group and could meet later as the medals are contested, but the victory is an important morale-booster for the U.S., who lead the medals table after 10 days.
The 19,300 capacity Canada Ice Hockey Palace was crammed to the rafters and the streets were emptied as millions watched on television, but it did not go according to the script for Canada.
Much was expected of 22-year-old Sidney Crosby, who led the Pittsburgh Penguins to the Stanley Cup last season, but it was the Americans who scored first after just 41 seconds as Brian Rafalski beat veteran netminder Martin Brodeur.
Eric Staal leveled for the Canadians on eight minutes and 53 seconds but the U.S. responded immediately as Rafalski scored his second of the night.
Dany Heatley pulled Canada level again in the second period, but the U.S. went two goals clear as Chris Drury of the New York Rangers and Jamie Langenbrunner scored.
Drury was sent to the penalty box to leave the U.S. short-handed and Rick Nash centered for Crosby to convert for Canada's third to make the score 4-3.
That set up a frantic finale for the last three minutes and with Brodeur joining the action it set up the Americans to score the clinching fifth as Canada lost possession and Ryan Kesler broke to score into an open net.
Crosby paid compliment to U.S. keeper Ryan Miller after the defeat and looked ahead to the later matches.
"It is one game and you run into a hot goalie (Miller) now and then. We were pressing to tie the game and he made some big saves."
Earlier, Russia beat the Czech Republic 4-2 in their preliminary round clash to step up their campaign.