NEW YORK, FEB. 26 -- It has been 25 months since Gwen Torrence lost an indoor sprint. The 22-year-old University of Georgia graduate stretched her unbeaten streak to 40 tonight with a charge from behind that caught Evelyn Ashford at the tape in the 55-meter highlight of the 100th anniversary USA/Mobil Track and Field Championships.

Torrence originally was declared the outright winner. But almost three hours later, the meet referee, on appeal, checked the photograph and announced the race was a dead heat.

Ashford, holder of the women's world record for 100 meters outdoors, shot out of the blocks clearly ahead of Torrence, who reduced the lead over the last half. The clock had both runners in 6.66 seconds.

"I wasn't sure if I won; I thought Evelyn nipped me at the tape," Torrence said. "The blocks slipped a little and I didn't feel comfortable in the first part of the race. I just didn't have time to get them set correctly. I guess I'm too tall for these blocks."

The Torrence-Ashford battle proved the closest of a number of exciting duels that helped make up for an overall entry list bordering on the mediocre.

Julie Rocheleau of Canada upset Jackie Joyner-Kersee in the 55-meter hurdles, Diane Dixon overhauled Valerie Brisco in the women's 400 meters and Antonio McKay fought off gallant Willie Smith in the men's 400.

Rocheleau made a perfect start hold up as she took the hurdles in 7.40, slicing seven-hundredths of a second off the Canadian record she set in an afternoon semifinal.

Joyner-Kersee desperately tried to reduce her early deficit, but she banged the third hurdle and went slightly off stride, then crashed into the fifth hurdle and fell across the finish line, placing fifth.

"This is the first time in my whole life I beat Jackie," said Rocheleau, who prefers to run without socks. "I hit the fourth hurdle and I thought, 'Oh, no.' But when Jackie hit the fifth hurdle and I hit the tape, that was it."

Joyner-Kersee said, "The blocks slipped a little, so I never was in sync with my steps. The fall didn't hurt much except my pride."

Qualifying for the 400 is strictly on time and, for the second straight year, Dixon set a U.S. indoor record in her semifinal. Today's time was 51.95, slicing five-hundredths from her 1987 mark.

In the final, Brisco followed her prerace plan by grabbing the early lead and forcing Dixon to pass her on the tight Madison Square Garden track. Dixon finally got by on the last turn and earned her sixth straight title in 52.51.

McKay, the world indoor champion, won his afternoon semifinal in 46.99, matching the best time ever on a 160-yard track. Five minutes later, Smith, a three-time Olympian who will be 32 on Sunday, reduced that mark to 46.97.

Smith gave it a big try in the final, too, but McKay held him off and won in a remarkable 46.55.

"I wanted to get the record back," said McKay, overall winner of the men's Grand Prix and a total of $12,700.

Ray Brown, the University of Virginia graduate from Washington, D.C., picked up a program today, saw the finish picture of last year's controversial loss to Stanley Redwine, and said, "I don't think about it too much, but when I saw the picture today, I still thought I crossed the line first."

This time, Brown made sure he would not be beaten by a photo interpretation. He ran away with the race in 1:47.66, establishing a meet record in the process.

Greg Foster had no difficulty winning his fifth hurdles title, covering the 55 meters in 6.93 seconds. Emmit King won the 55-meter sprint just as easily in 6.06.

Doina Melinte of Romania enjoyed a runaway in the women's mile, although her time of 4:36.68 was almost 18 seconds off the world indoor record she set two weeks ago. Alisa Harvey of Fairfax, Va., was second in 4:39.61.

Marcus O'Sullivan of Ireland completed an unbeaten indoor season in the mile, winning without difficulty in 3:59.85. Jim Spivey took the 3,000 meters in 7:52.91.

Maryanne Torrellas set a U.S. indoor record of 12:45.38 in the 3,000-meter walk and was rewarded with the $10,000 bonus as top woman athlete in the overall Mobil Grand Prix, besides collecting $2,100 in event money.

A year ago, most of the meet's excitement came early in the day, as Heike Drechsler (24-0 1/4 long jump) and Mike Conley (58-3 1/4 triple jump) set world indoor records.

Today's results were less inspiring. Sheila Echols pulled out the long jump with a final attempt of 21 feet, more than three feet shy of Drechsler. Then Ray Kimble took the triple jump at 56-3 1/4, two feet off Conley's effort. Larry Myricks took his fifth title in the men's long jump at 27-0 1/2.