At the end, 7,000 people stood as one, chanting "U.S.A., U.S.A.," as the American hockey team salvaged what had been an otherwise dismal day for the U.S. Olympic team with a stunning 7-3 victory over highly regarded Czechoslovakia tonight.

Buzz Schneider scored two goals, including one that broke a 2-2 tie and another that broke open the hockey game, and goaltender Jim Craig made all manner of critical saves as the Americans made it clear they now are legitimate contenders for a medal.

The U..s., after tying Sweden, 2-2, in its opener, has a 1-0-1 record in the Blue division of the competition and will be favored to win its next three games against Norway, Romania and West Germany. That would get the Yanks into the final championship flight, and a possible meeting against the Soviet Union, the solid favorite for a gold medal.

The Americans started out swarming from the opening faceoff tonight, and thumping, too, particularly in the second period when the U.S. team broke a 2-2 tie with goals by Schneider and Mark Johnson, "the man who makes us go," according to U.S. Coach Herb Brooks.

Johnson went straight to the Olympic infirmary after the game because he suffered a shoulder injury late in the third period when Czech defenseman Jan Neliba took what Brooks described as a cheap shot and rammed Johnson into the boards.

"It's not a separation," Brooks said, "I don't know the medical term for it. It's like a dislocation. It popped in and out. It might be okay in a couple of days. We just don't know. His loss would be crucial."

Three other men also made the Americans go, and go, and go some more tonight, Schneider and linemates Mark Pavelich and John Harrington swarmed all over the Czechs, applying heat and hot shots all night long.

Pavelich added a goal and an assist, Harrington had two assists and Johnson had a goal and an assist in a game that never was in doubt after Schneider gave the U.S. team a 6-2 lead at 3:59 of the third period, the fourth straight American goal and second within a minute.

Harrington was mostly responsible. He was in back of the net, closely guarded by two Czech defenders, but somehow managed to get the puck out on Schneider's stick all alone in front of the Czech net.

Schneider unloaded a hard wrist shot that sent Czech goalie Jiri Kralik sprawling and started still another wild American celebration, both on and off the ice.

Sixty seconds before that, Dave Christian broke in on the Czech goal with a man on his back, but still managed to get off a shot. Kralik saved that attempt, but Phil Verchota poked in the rebound for a 5-2 lead at 2:59 of the period.

Craig, meanwhile, may have made the game's biggest play early in the second period. At that point, his team still was tied with the Czechs at 2-2 and had a man advantage on a power play.

The Americans have had difficulty scoring in those situations most of the pre-Olympic season, and tonight was no exception. And they very nearly got burned when Peter Stastny, one of three Czech brothers on the same line (the real swinging Czech brothers) broke in alone on Craig from the right side.

Stastny fired a low shot at the right corner and Craig just did manage to get a skate on it, deflecting the shot and preventing what surely would have been a terribly demoralizing goal.

Craig made another point-blank save after the Czechs had cut the U.S. lead to 6-3 at 5:36 of the third period. Miroslav Dvorak was all alone in front of the net, but Craig blocked his low shot with his pad.

The Americans then added their final goal when Rob McLanahan made a superb individual effort, even as he was being hooked from behind, to slide a low shot past Kralik for the final 7-3 margin at 10:54 of the last period.

"The long and short of it is that we could not stand around in awe of those people," Brooks said." We had to use our youthfulness as an asset, not a liability. With youthfulness comes hungryness and hungry athletes are going to reap rewards."