Stanford University freshman Debi Thomas took a big first step toward upsetting defending titlist Tiffany Chin and becoming the United States' first black skating champion today by winning the compulsory figures competition.

This is the first U.S. compulsory Thomas, 18, of San Jose has won. She was runner-up to Chin at last year's U.S. nationals.

"The figures we had to do were the one group that my coach and I didn't want, and we ended up winning them," Thomas said. "It's a real confidence booster."

"I feel I'm more prepared for the freestyle," said Chin. "I came in here without top quality figures. I've only done serious training since the second week in December."

Thomas, a medical microbiology major, finished the three compulsory figures with 107.10 points and 12 ordinals. Chin, 18, a Toluca Lake, Calif., resident who trains in Denver, finished with 104.60 points and 20 ordinals. Third, with 104.20 points and 22 ordinals, was 1985 bronze medalist Caryn Kadavy, 18, an Erie, Pa., native who skates out of Colorado Springs.

The figures count as 30 percent of the final score. The short program is Friday.

In the senior pairs, Gillian Wachsman and Todd Waggoner won the short program over defending champions Jill Watson and Peter Oppegard. Wachsman, of Riverside, Conn., and Waggoner, of Schaumburg, Ill., performed a nearly flawless routine, while Watson stumbled coming out of a simple jump.

Liane Moscato, 13, of the Skating Club of Boston, won the novice women's division, placing first in compulsories and second in free skating.

Rudy Galindo, 16, of Berkeley, Calif., was second in the junior men's short program but held on to first place heading into the freestyle finals Thursday. Erik Larson, 17, of San Diego was second after two rounds.

The men's novice champion was Cameron Birky, 15, of Danville, Calif. Birky totaled 127.50 points and 16 ordinals. David Warnke of Laurel, Md., finished 12th with 104.93 points and 96 ordinals.

Tracie Brown, 14, of the Skating Club of Boston, won the junior women's compulsories with 15 ordinals and 98.10 points. Alexandria's Lilly Lee was in ninth place with 81 ordinals and 93.40 points.

Colette Huber, 20, of the Los Angeles Figure Skating Club, and Ron Kravette, 22, of the Rim of the World Skating Club, won junior compulsory ice dancing.