TURIN, Italy — The United States couldn't possibly lose, and it didn't.

The Czech Republic couldn't possibly lose, but somehow did. The Czechs suffered a stunning 3-2 defeat to Switzerland on Thursday, temporarily stopping their predicted drive to an Olympic hockey medal.

One night after a disappointing opening-game tie with Latvia stirred doubts about the Americans' medal chances, they bounced back to beat talent-thin Kazakhstan 4-1.

Several U.S. players said the difference was simple: getting some sleep after not arriving in Turin until Tuesday, and becoming reacquainted with international play.

"Obviously, you're going to have jitters the first time you play in this event, but at the end of the day, it's still the same game," goalie Rick DiPietro said.

For DiPietro, it was a day for stars, stripes and not many stops. DiPietro dressed in patriotic stars-and-stripes pads and wore a mask that bears the image of the helicopter his father piloted in the Vietnam War. But he only had to make 11 saves for the win.

While the Americans' victory was expected, Switzerland's upset of world champion Czech Republic was a shocker. The Swiss lost 5-0 Wednesday to Finland and weren't given much of a shot to get into the quarterfinals.

Colorado Avalanche goalie Dave Aebischer made key stop after key stop in turning aside 40 shots. His exceptional play allowed the Swiss, who have only two NHL players, to beat a team seen as the biggest gold-medal threat to favored Canada.

"I think it's by far the biggest win in Swiss hockey — since I've been playing. Even in history," said Mark Streit, a Montreal Canadiens defenseman. "It's kind of a miracle."

The Czechs played without injured starting goalie Dominik Hasek, who pulled himself out of the Olympics this morning. He was injured minutes into an opening-game win over Germany on Wednesday.

Team officials said Hasek had a leg injury, but backup Czech goalie Tomas Vokoun said Hasek told him it was a groin problem. The 41-year-old Hasek, bothered by groin problems in recent seasons, will return to Ottawa for treatment and it is not known if he will miss any Senators' games following the Olympic break.

As for the Swiss upset, Canada captain Joe Sakic wasn't surprised with how well Aebischer played. The two are Colorado Avalanche teammates and, Sakic said, "He was playing that way for us" just before the Olympic break.

Still, Sakic said the Swiss upset caught Canada's attention, since the teams play on Saturday. Canada cruised to its second easy victory in as many days, beating Germany 5-1 on goals by Sakic, Wade Redden and Simon Gagne in the first period.

While the opposition has been weak, Canada is playing much better at the start than it did in Salt Lake City in 2002, when it lost to Sweden 5-2 and edged Germany 3-2 before going on to win the gold medal.

Sakic suggests it may be because this is the third international tournament in five years for a number of these Canadians; by contrast, few had played together before the 2002 games.

"I think we are starting to jell and coming together," Todd Bertuzzi said.

In other games on the second of five days of round-robin group play, Russia rebounded from an opening-game loss to Slovakia to dominate Sweden 5-0; Slovakia beat Latvia 6-3; and Finland beat Italy 6-0. Slovakia and Finland are 2-0.

Evgeni Nabokov, benched by the San Jose Sharks immediately before the Olympics, turned aside 24 shots for Russia and the Swedes, without star Peter Forsberg, were 0-for-7 on the power play. Nabokov and his teammates were motivated after losing to Slovakia 5-3 only 18 hours before.

"It's unbelievable to win against Sweden," defenseman Darius Kasparaitis said.

Finland has outscored Switzerland and Italy by a combined 11-0. Now comes the hard part: the Czechs on Saturday and Canada on Sunday.

"If you look at the lineups, they are better on paper but things are not decided on paper," said Saku Koivu, who scored a goal. "There are strange things that can happen in a tournament like this, and the team with the most talent doesn't always win."

Slovakia, with its 18 NHL players, also is looking like a medal contender.

"It's too early to talk about gold, but we didn't fly 15 hours just to play here," Los Angeles Kings forward Pavol Demitra said.