-- So much for the thought that Serena Williams is unbeatable. Justine Henin-Hardenne emphatically ended Williams's 21-0 start to the season by beating the world's No. 1 player, 6-3, 6-4, today for the Family Circle Cup title.

"This doesn't change anything about the great champion that Serena is. But it means that today we could see that we can do these things against her, and she can be frustrated, too," Henin-Hardenne said. "I think it's good for the other players that we can see that."

Williams's last loss came against another Belgian, Kim Clijsters, in the 2002 season-ending Tour Championship in November.

She issued a warning to future opponents.

"Sometimes you need to lose," Williams said. "I'm so motivated now. I can just feel it coming on again. So you've got to watch out."

Perhaps what was most stunning was the way the momentum turned after Williams opened the final at the clay-court event by winning the first three games.

Her fourth-ranked opponent won six games in a row, taking 23 of the last 26 points in the first set. With Henin-Hardenne's smooth strokes right on target, she also overcame a 2-0 deficit in the second set.

The Belgian entered the match with a 1-4 career mark against Williams, who has won the last four major tournaments in a row: the French Open, Wimbledon and U.S. Open last year, and the Australian Open in January.

That streak led to talk that Williams might be able to get through 2003 without a loss. But she repeatedly has said a perfect season was a lofty goal she never expected to reach.

"I think you guys dwelled on it more than I did," she said today.

Williams showed some shakiness in the semifinals against former No. 1 Lindsay Davenport, blowing a big second-set lead.

Henin-Hardenne made Williams pay for errors, running down shots into the corners and forcing the American to go deeper into points.

"I was a little bit nervous at the first," said Henin-Hardenne, who lost to Williams's older sister, Venus, in the 2001 Wimbledon final. "But then she began to make some mistakes."

It's Henin-Hardenne's second title of the year and improved her match record to 21-4. She won a tournament on hard courts at Dubai in February, beating Jennifer Capriati and Monica Seles in consecutive matches.

Today, Williams dropped her racket in frustration after putting a forehand into the net at 3-3 in the second set. She hit long two points later to fall behind, 4-3. In the final game, Williams hit a backhand approach into the net.

The clay might have dulled her serve a bit, giving the swift Henin-Hardenne more of a chance to get to balls. Williams had nine aces against Davenport, zero today.

"I think it's my best surface for sure," Henin-Hardenne said. "This should give me a lot of confidence for the rest of the season."

After 21 straight wins, No. 1 Serena Williams won't go unbeaten in 2003, falling in straight sets to fourth-ranked Justine Henin-Hardenne.