Tomas Dvorak of the Czech Republic broke Dan O'Brien's decathlon world record by 103 points yesterday and could have broken the "magical barrier" of 9,000 points if not for a mistake in the final 1,500-meter event at a European Cup competition in Prague.

In smashing O'Brien's mark with a total of 8,994 points, Dvorak had a legitimate shot at becoming the first decathlete to accumulate 9,000 points. He needed to run the 1,500 in 4 minutes 36.34 seconds, more than six seconds slower than his best of 4:29.69. To tie O'Brien's record, Dvorak needed to run a comfortable 4:53.87.

He finished in 4:37.20, after making a mistake in the second lap.

"We slowed down a bit and we got punished," Dvorak said. "I had enough power in the last lap, but it was too late."

O'Brien, the 1996 Olympic gold medalist and three-time world champion, had set the record of 8,891 points in 1992. Dvorak's best previous score was 8,837, at the 1997 world championships in Athens.

Dvorak, the 1997 world champion and 1996 Olympic bronze medalist, had three personal bests on Saturday; 10.54 seconds in the 100 meters; 25 feet 11 inches in the long jump, and 55-0 in the shot put.

Yesterday, Dvorak was fastest in the 110-meter hurdles in 13.73, and had another personal best with 158-6 in the discus throw.

"If I had performed beyond 9,000 points, I would have had a message for O'Brien, but now it's better to shut up," Dvorak said, sipping champagne. . . .

Khalid Khannouchi of Morocco and Elana Meyer of South Africa won titles in the 10-kilometer Peachtree Road Race in Atlanta as Africans swept the first 10 places in both the men's and women's divisions.

Khannouchi covered the 6.2 miles in 27:45, for his second consecutive victory. Meyer won the women's race in 31:34.

Golf

Dempsey Is Stable

Caddie Garland Dempsey was upgraded to fair condition, one day after he collapsed during the third round of the Western Open in Lemont, Ill.

Dempsey, John Maginnes' caddie, remains in the intensive care unit at Palos Community Hospital. Dempsey's family has asked that no information other than his condition be released.

Dempsey's heart stopped when he collapsed on the 15th hole Saturday.

World University Games

Speed Racer

Mark Warkentin trains for swimming's equivalent of the marathon. Yesterday, he did a fair impression of a sprinter.

Competing in the 200-meter freestyle at an international event for the first time, the native of Santa Barbara, Calif., won a gold medal at the University Games, one of five medals the United States earned on the first day of swimming competition in Palma de Mallorca in the Balearic Islands.

"It came as a shock. I was swimming, and then I won," said Warkentin, who was timed in 1:51.30, in becoming the first U.S. swimmer since Matt Biondi in 1985 to win the 200 freestyle at the University Games.

"They raised the flag. That's never happened to me before. I've only seen that on TV. You dream about moments like that."

The United States won the gold in the women's 800 freestyle when the team of Rada Owen, Kimberly Black, Caroline Kilian and Kathryn Zambone was timed in 8:13.41.

CAPTION: Tomas Dvorak of the Czech Republic celebrates his world record of 8,994 points in the decathlon at a European Cup meet in Prague.