Artur Yusupov, the Soviet grandmaster, brilliantly defeated the Canadian grandmaster Kevin Spraggett in a sudden-death playoff Saturday to win their world championship candidates quarterfinalmatch and advance to the semifinal stage.

The match was played in Quebec.After six games and two tie-breaker games, all played at the standard 40 moves in two hours, the match was deadlocked. Yusupov won the first sudden-death game. Spraggett and Yusupov split the $40,000 purse.

In two other concurrent quarterfinals, Anatoly Karpov of the Soviet Union defeated Johann Hjartarson of Iceland, 31/2-11/2, in Seattle.

In Antwerp, Belgium, Lajos Portisch of Hungary leads Jan Timman of the Netherlands, 2-1, with the fourth game adjourned.

The winner of the candidates, in a series of knockout matches, will challenge the world champion, Gary Kasparov, in a grueling 10-week title bout scheduled for 1990.

The British grandmaster, Jonathan Speelman, who won the quarterfinals in August, was the first player to make it to the semifinals.