CALGARY, FEB. 20 -- Figure skater Brian Boitano won the United States' first gold medal of the XV Winter Olympics tonight when he defeated world champion Brian Orser of Canada in a battle of nearly flawless performances at the Saddledome.

Earlier in the evening, East German speed skater Andre Hoffmann narrowly defeated American Eric Flaim to win the gold medal in the men's 1,500 meters, giving his nation its second gold medal of the day and the United States its first silver medal.

Flaim, just 6/100ths of a second behind Hoffmann, won the first medal since 1980 for a U.S. speed skating team that has been particularly beleaguered here. Pairs figure skaters Jill Watson and Peter Oppegard had won the only other U.S. medal at these Olympics, a bronze last Tuesday.

Boitano, 24, of Sunnyvale, Calif., won by the narrowest of margins over Orser, his close rival and friend. Five judges rated Boitano higher than Orser; four gave higher marks to Orser, who also won the silver medal in the 1984 Olympics when American Scott Hamilton won the gold medal.

Soviet Victor Petrenko won the bronze medal by passing countryman Alexander Fadeev, who entered the men's long program in third place.

"I want to thank America for all its support," Boitano said. "I consider this medal a victory for all of America."

At the Olympic Oval, Hoffmann's time was 1:52.06; Flaim's was 1:52.12. Both broke the existing world record of 1:52.50.

Michael Hadschieff of Austria won the bronze and also bettered the mark in 1:52.31.

Flaim, 20,of Pembroke, Mass., had finished fourth in both the 1,000 and 5,000 races.

He raced in the first pair tonight, and when he finished and saw his time, he raised his arms in jubilation and stuck his index finger high into the air. Then, when he watched the second pair finish and realized how good his time was, he looked into a television camera and mouthed the word, "Gold."

"I had a strong last lap and I was thinking, hopefully, that maybe it would stand, but it didn't," Flaim said.

Hoffman raced in the third pair, and just slipped past Flaim to win East Germany's sixth gold medal, the most for any country at these Olympics.

The Soviet Union has 15 medals, five of them gold, to lead the overall medal count. East Germany has 10 total medals.

At Canmore, U.S. biathlete Josh Thompson, who was second in the 1987 world championships and was expected to win a medal here, finished a disappointing 25th in the 20-kilometer biathlon, won by Frank-Peter Roetsch, an East German police lieutenant.

Roetsch finished the combination cross country ski race and shooting range competition in 56 minutes 33.33 seconds. Valeri Medvedtsev of the Soviet Union won the silver medal in 56:54.62; Johann Passler of Italy won the bronze in 57:10.12.

Thompson, of Gunnison, Colo., finished in 1:01:29.45, with five penalty minutes tacked on for five misses in the shooting competition. He was nearly in tears when he crossed the finish line.

"You just can't do it with shooting like that," Thompson said.

In other events earlier in the day, the big story was a springlike, 60-degree-plus afternoon that brought shirt-sleeve crowds to the Winter Olympics.

The Big Thaw had a profound effect on the first day of the two-man bobsled competition, where Soviet driver Ianis Kipours took an unexpected lead over defending gold medalist Wolfgang Hoppe of East Germany.

The temperatures and bright sunshine caused the ice on the bobsled run at Olympic Park to deteriorate throughout the day. Kipours was the sixth man to race in the second round today; Hoppe's sled was the 29th, when times were much slower.

Hoppe broke the course record by more than two seconds on his first run with a time of 57.06 seconds. But, on his second run, he managed only 59.26 seconds for a total of 1:56.32. Kipours, who finished fourth at the 1984 Olympics, had times of 57.43 seconds and 58.05 for a total of 1:55.48.

"The grooves in the ice were so deep at the start of the second run, I was saying, 'Hello, is anybody down there?' " said American driver Matt Roy, who was 24th after the two heats. "It was tough to get going out of those holes."

Willie Gault, the Chicago Bears receiver whose presence on the U.S. team here created a controversy, did not compete but did go down the track as one of the race "forerunners" who test the course before the races.

Gault is not competing because Coach Jeff Jost said he was not one of the top two pushers on the roster. But Gault and Randy Will took their USA 3 sled down the course as forerunners, and Gault said the run proved he should be racing.

In hockey, world champion Sweden (2-0-2) was tied by Finland, 3-3, but clinched a berth in the medal round when Switzerland beat Poland, 4-1.

Canada (3-1) also qualified with a 9-5 victory over France. Finland (2-1-1) is expected to be the third team to qualify from the A pool.

The U.S. hockey team plays West Germany Sunday at 8:15 p.m. (EST). The Americans need to win the game by two goals to be assured of a spot in the medal round. However, if Czechoslovakia defeats or ties the Soviet Union, the U.S. needs only to win Sunday to advance.

At Nakiska, Carole Merle of France and Maria Walliser of Switzerland finished first and second in the downhill portion of the women's Alpine combined skiing, but both said later they don't think they can win a medal.

Merle, a giant slalom specialist, and Walliser, a downhill star, are not known for their prowess on a slalom course. Unfortunately for them, the second portion of the combined is a slalom race Sunday.

Slalom specialists Brigitte Oertli and Vreni Schneider of Switzerland and Anita Wachter of Austria are within reach of the leaders and are expected to win medals.

The men's super giant slalom also will be held Sunday. Pirmin Zurbriggen of Switzerland is favored to win his second gold medal, but he will be challenged by Italian sensation Alberto Tomba, who will be competing for the first time in the Olympics. Zurbriggen won the men's downhill and was leading the combined when he hooked a gate during the slalom portion.