DUBAI, United Arab Emirates (AP) _ The top U.S. chess player, 26-year-old Yasser Seirawan, defeated World Champion Garri Kasparov late Sunday during the 8th round of the international chess olympiad.

Kasparov adjourned in a hopeless position and resigned the game an hour later.

''Of course I'm very pleased,'' Seirawan said. ''It's unexpected and I was lucky. I'm already thinking about my next game tomorrow against Hungary.''

Kasparov late Sunday night walked into the lounge of the Hilton Hotel where the American team was relaxing and said he was resigning the game.

''Don't bother analyzing the position,'' he told the Americans.

Seirawan, of Seattle, Wash., and Kasparov discussed the game for a few minutes, as the other members of the American team looked on.

The Soviets and the Americans played to draws in two games Sunday, and another, between Larry Christiansen and Soviet grandmaster Andre Sokolov, was adjourned. The drawn games were between Lubos Kavalek and Soviet Artur Yusupov, and American Maxim Dlugy and Rafael Vaganian.

Christiansen had a good chance of drawing Sokolov, the world's third-ranked player.

Each win by a player earns the team a point, and a draw is worth a half- point. The men's teams play four games per round.

England has the lead in the 27th chess olympiad with 23.5 points, followed by Hungary with 22.5 points, the United States 22 and one game adjourned, Bulgaria with 22, the Soviet Union 20.5 with one game adjourned, and Yugoslavia, Spain and Switzerland tied at 20.5 points each.

In the early stages of their game, Kasparov built up a positional advantage with the black pieces against Seirawan.

Kasparov tried to force the position by creating complications, marching his central pawns down the board. But Seirawan's pawn phalanx on the king-side was quicker, and Kasparov resigned, unable to stop Seirawan from promoting a pawn into a queen.

In other matches Sunday, England defeated Iceland 4-0, Hungary beat Yugoslavia 2.5-1.5 and Bulgaria downed Scotland 3-1.

The U.S. women's team played to a 1.5-1.5 tie with Argentina, with American Rachel Crotto losing to I. Burijovich. American Ivona Jezierska defeated C. Herrera, and Gina Linn drew with M. Rizoo of Argentina.