For 31 minutes, Joyce Walker sat and wondered how a team's leading scorer could not play at all. But her coach, Jill Hutchison, had a secret and didn't want to reveal it to Yugoslavia until absolutely necessary.

With 9:11 to play, and the United States tied with Yugoslavia, it became absolutely necessary. So into the game came Walker, and into the World University championship game went the U.S. women. Walker's eight points in less than six minutes rallied the Americans to an 86-85 victory tonight in a semifinal game.

The U.S. men's team won the bronze medal tonight by defeating Cuba, 119-91. Devin Durrant had 25 points for the United States. Canada won the gold medal by defeating Yugoslavia, 83-68, as Danny Meagher, who plays for Duke, scored 15 points.

The U.S. men won the gold in the 1600-meter relay, with Elliot Tabron, Alonzo Babers, Sunder Nix and Cliff Wiley edging the Soviets with a time of 3:01.24. Danny Goldie of Bullis Prep in Potomac, Md., and Stanford defeated Soviet Alexandr Zverev, 4-6, 7-5, 6-1, to advance to the tennis singles final Sunday.

Yugoslavia's women played the last 1:47 without their star, Jasmina Perazic, the all-America from the University of Maryland. Having scored 21 points, she was taken out because Coach Milan Vasojevich was disgusted with the way she played defense against her American friends.

The victory enabled the United States to advance to Sunday night's gold-medal game against Romania, which defeated China, 97-63, in the first semifinal. Romania routed the United States, 87-71, Thursday.

With Walker's heroics, the U.S. team was able to hold the lead down the stretch. It secured the win with 13 seconds left when Oregon State's Carol Menken-Schaudt made a short jumper for an 86-83 lead.

Yugoslavia scored with four seconds left, but the Americans got the ball in bounds and celebrated at midcourt.

The United States had been trailing much of the second half, but tied at 63 with 10:22 left. It was risky leaving Walker, the competition's sixth-leading scorer, on the bench, but as Hutchison explained, "She's been most effective coming off the bench, giving us a quick basket. When she's in from the beginning, they notice how well she shoots and key the defense around her."

With 9:11 left, Hutchison slipped Walker into the game quietly. The only Yugoslavian who seemed to notice was Perazic, who is one of Walker's best friends. "We play pick-up games together," Perazic said. "Not only is she the greatest person in the world, she's got the best shot of anybody in the United States. I told them to watch her. I knew what she would do. But nobody listened."

Walker, from Louisiana State, said, "After the first one, I felt I was into the flow and they were leaving me wide open. So I kept shooting."

Perazic, who has averaged a Universiade-high 22 points per game, had bedazzled the crowd with an uncommon flair and knowledge of the game. But Vasojevich benched her for six minutes in the first half because she wasn't playing aggressive defense.

"I did wonder what could happen if I was on the floor that last minute or so," Perazic said. "But Milan was right. I wasn't playing aggressive defense the entire game. When he called me out, I knew right away why he did it.

"I didn't want to play against the United States, I swear I didn't. Some of us are such good friends. I had to guard Cathy Boswell some, and I felt kinda bad about it.

"That shouldn't have been a problem, but . . . I don't know. I told Joyce and Cathy last night I'd rather not play against them. I love the way the Americans play with enthusiasm. They don't have that in Europe. I wished we played that way, but . . . "