A week ago, world chess champion Gary Kasparov was in seventh place in the third World Cup tournament in Reykjavik, Iceland. He had suffered a humiliating defeat in the seventh round by falling into a routine trap and lost his queen and the game to Andrei Sokolov.

But Kasparov is proving to be a real "money player." Earlier this year he retained his world title by a smashing victory in the final game with Anatoly Karpov when it appeared that he had lost his title.In the current tournament, at the end of nine rounds Kasparov had won only two games.

But, in another spurt, he won the tournament by winning three of his four final games.

Kasparov took the $20,000 first prize after drawing his final game with the Yugoslavian grandmaster, Predrag Nikolic.

Kasparov's nearest challenger, Soviet grandmaster Alexander Beljavsky, lost to former world champion Boris Spaasky and had to be content with second place.

Another Soviet former world champion, Mikhail Tal, finished third.

Kasparov looked in indifferent form throughout most of the tournament. He finally scored a total of 11 points in the 17-round contest.

Belyavsky and Kasparov went into the final round sharing the lead with 101/2 points each. But Spaasky defeated Belyavsky in the final round, and as a result, Belyavsky scored no points. Kasparov scored half a point for his draw with Nikolic.

Kasparov's victory places him in the lead in the six-tournament World Cup series, with a total of 561/2 points, two points ahead of Karpov. Karpov did not play in the Iceland tournament.

The World Cup series is the second most important event in chess after the individual world championship organized by the World Chess Federation (FIDE). The six tournaments in the World Cup series, which ends in 1989, are spread over two years. Prize money totals $1.2 million.

The first tournament in the series, held in Brussels, was won by Karpov. Kasparov won the second tournament in Belfort, France.

The fourth tournament will be in Barcelona, the fifth in Rotterdam, and the sixth in Skelleftea, Sweden.

In the three tournaments so far, Kasparov and Karpov have not played in the same tournaments. Kasparov played in the second and third and won. Karpov played only in the first, which he won.

Not only do the winners of each tournament receive a significant prize, but also the person with the highest total combined score at the end of the series will receive the grand prize.

Leading final positions in the just-completed tournament are: Kasparov 11 points, Beljavsky 101/2, Tal 10, Hjartarson and Elhvest each 91/2, Yusupov, Sax and Timman, 9, Speelman, Nunn and Andersson each 81/2.

-THE WINNAH - In a stunning surprise, a virtual unknown, 15-year-old Joel Lautier of France, won the world junior championship in Adelaide, Australia.

In the 13-round Swiss-system tournament for players under 20 years of age, Lautier scored 9-4, which was equaled by the Soviet luminaries Vassily Ivanchuk, Boris Gelfand and G. Serper, but the young Frenchman beat them on tie-break points.

Tied for fifth to seventh places were Ferdinard Heilers of Sweden, Matthias Wahls of West Germany and Vladimir Akopian of the Soviet Union. They each tallied 8 1/2-4 1/2.

The best result by an American entrant was Patrick Wolff's 8-5 for an eighth-place tie.

Stuart Rachels, also of the United States, scored 7 1/2-5 1/2 to be included in a 13th-place tie.

-CONGRATULATIONS TO THE SOLVERS! Covert Copier, Hal Wilkinson, John Nielson, Kenneth L. Cook, James Palmer, Edwin O. Smith, Raymond Linner, Dr. Harold Rosenberg, Joan Nay, Hal Harmon, Robert Tanner, Jim Fullmer, Kay Lundstrom, Gordon W. Green, Paul R. Lindeman, Gene Woodruff, Ted Pathakis, David Cook, Prof. Ardean Watts, William DeVroom and Steve Farnsworth.