Obviously, this is NOT an upset on quite the same level as 1980's Miracle on Ice, which might have been the biggest upset (actually, it was a couple of upsets) in the history of sport, at least not with the current American squad playing with a roster full of NHL players (as opposed to college kids playing against NHL-caliber players in 1980 from the Cold War era Soviet Union). But that being said, as the announcers noted tonight, the American team may consist of NHL guys, but "only a handful of them are recognizable NHL players." In contrast, Canada's team (also consisting entirely of NHL players) has been described as a veritable All-Star team of NHL guys. AND, tonight's game was played in Canada, which held a huge home ice advantage in this one. Bottom line: Canada was heavily favored here, the US has not beaten Canada in Olympic hockey EVER to my knowledge (or least not in many, many decades), and this was a HUGE upset. I only caught the third period, and it was extremely exciting. Great win. But this is only the preliminary round. Plenty of hockey left to play.
http://sportsillustrated.cnn.com/2010/olympics/2010/02/21/usa.canada.blog/index.html?eref=sihp