Five minutes before the celebrations could begin, with the United States Olympic hockey team clinging to a tenuous 4-3 lead over the heavily-favored squad from the Soviet Union, coach Herb Brooks could be heard above the din of 8500 frenzied fans. "Play your game!" he shouted at his players, "Play your game!"

They did. The young Americans stunned the hockey world last night and took a giant step towards this country's first Olympic gold medal in the sport since 1960 by upsetting the more experienced Soviets, 4-3, in an emotion-filled contest in Lake Placid last night.

Trying to emulate their predecessors of 20 years ago--who knocked off the Soviets and went on to take the gold at the Squaw Valley, Calif., games--the United States plays Finland Sunday afternoon in the final day of medals round competition.

The undefeated Americans, overcoming their opponents' famed passing attack with aggressive forechecking and superb "nyetminding" by former B.U. star Jim Craig, came up with two goals midway through the final stanza after trailing, 3-2, after two periods.

Mark Johnson rapped in a loose puck with less than 12 minutes left in regulation, and a wristshot by captain Mike Eruzione beat Soviet netminder Vladimir Myshkin 1:21 later, to secure the victory.

Soviet coach Viktor Tikhonov had put Myshkin in the nets to replace starter Vladislav Tretiak at the end of the first period, which ended in a 2-2 deadlock.

The decision might well have been inspired by the Americans' tying goal, which Mark Johnson put in--only one second before the session concluded--after Tretiak sloppily kicked out Ken Morrow's 100-foot slapshot.

Earlier, the Americans had fallen behind, 2-1, on scores by Vladimir Krutov and Sergei Makarov sandwiched around a blast by the U.S.

As they did all night, the older and more experienced Soviets, who a year ago this month humiliated a collection of National Hockey League all-stars, often threatened in the U.S. zone but were repeatedly frustrated by Craig. (Craig faced 39 Soviet shots, while the Americans mustered only 16.)

The second period saw the Soviets regain the lead on a power-play breakaway goal by Aleksandr Maltsev, but they could go no further. The Americans, though behind, never panicked and stuck to their scrappy style. They played their game, and--charged with the chants of "USA! USA!"--it sufficed.

In other action at the XIII Winter Olympics, Ingemar Stenmark of Sweden stormed back from fourth place in the men's slalom and captured his second gold medal. Phil Mahre of Yakima, Wash., who led after the first of two runs, took the silver half a second behind. Jacques Luethy of Switzerland finished third.

Mahre, who suffered a broken ankle in an accident only a year ago, became only the second American ever to win a silver in an Alpine event. Billy Kidd was the first, in 1964.

Today, record speed skating champion Eric Heiden goes for an unprecedented fifth gold medal in the 1500 meters.