Debi Thomas of the United States won the women's world figure skating championship tonight, defeating two-time champion Katarina Witt of East Germany.

"I'm delighted to have done a good job, to have skated so well for all the fans and all my friends at home," the 18-year-old Stanford University student said after a fine long program that included four triple jumps -- one fewer than when she won the U.S. championship last month.

Thomas' victory, the first in a world championship singles event by a black skater, gave the United States winners in both men's and women's competition. Brian Boitano won the men's title Thursday night.

Tiffany Chin, 18, finished third behind Witt, the 1984 Olympic champion.

"This is one step on the ladder to the Olympics in 1988," said Thomas, who was fifth in last year's world championships. "It was difficult to skate after Katarina tonight when she had done so well."

Witt's dramatic skating to the score of "West Side Story" earned two perfect scores of 6.0 for artistry and won the long program, but Thomas was second and that was enough.

"It was one of my best performances and I couldn't do anything more," Witt, 20, said. "She was better than me in the figures and the short program and deserved to win."

It was the second straight bronze at the worlds for Chin, who missed seven months of training last year with a muscle imbalance in her leg. Her long program, which was ranked fourth, included lots of jumps and a spectacular spin combination at the end.

Canadian Elisabeth Manley, who had the cleanest series of triple jumps, was ranked third in the long program to move up five positions to fifth overall behind Soviet Kira Ivanova, who was second going into the long program, but fell twice.

While outdone by Witt, Thomas' free-skating display was superb and earned her two scores of 5.9 for technique and two for artistry.

Thomas and her coach, Alex McGowan, decided to delete a triple loop jump she had landed in the U.S. championships, but the four she did all came off well.

"I don't believe it," a tearful Thomas said as she sat with her arms filled with flowers. "I even landed that double axel."