updated 2:20 a.m. ET Sept. 5, 2007

NEW YORK - A sullen Serena Williams exited the locker room, her racket bag slung across two shoulders, her U.S. Open over after a third consecutive Grand Slam loss to Justine Henin.

While Williams waited for a courtesy car at the player exit, her mother, who also is her coach, put an arm around her neck for a quick, consoling hug. Mom whispered something, and Williams looked straight ahead, apparently still not in any mood to dissect the defeat an hour after it ended.

Finding all the right angles and hanging tough on long rallies, Henin beat Williams 7-6 (3), 6-1 Tuesday night to reach the U.S. Open semifinals.

Williams’ postmatch news conference began with a query about whether she could explain what went wrong. Her reply: “No. I can’t. I’m sorry. Any more questions?”

“She made a lot of lucky shots,” Williams said a moment later, a white baseball cap pulled low over her eyes, “and I made a lot of errors.”

The formerly No. 1-ranked Williams is the active leader among women with eight Grand Slam titles, but current No. 1 Henin now has a chance to claim her seventh major.

“I was a bit concerned during the first set because I wasn’t aggressive enough. Then from the tiebreak until the end, I played unbelievable tennis,” Henin said after compiling a 30-17 edge in winners. “My tournament is not over — far from that.”

Her next opponent could be another Williams: Serena’s older sister, Venus, faces No. 3 Jelena Jankovic in the quarterfinals Wednesday night. Not much question for whom Henin will be rooting — she’s 1-7 against Venus Williams, 7-0 against Jankovic.

John G. Mabanglo / EPA Justine Henin celebrates after beating Serena Williams 7-6 (3), 6-1 in the quarterfinals of the U.S. Open on Tuesday.

“Every match is a final for me now,” Henin said. “If I have to play Venus, it will be a good challenge for me to play both sisters in the same tournament.”

Only once has someone beaten Serena and Venus Williams at a single Grand Slam: Martina Hingis did it at the 2001 Australian Open.

Henin beat the younger Williams at the French Open en route to her fourth title in five years there, and again at Wimbledon — both times also in the quarterfinals.

“I got a lot of confidence in Paris and London,” Henin said.

Their matchup at Wimbledon in July didn’t feature Williams at her absolute best: She could barely hit backhands after spraining her left thumb and hurting her left calf in the previous round. Because of the thumb, Williams withdrew from every event she was scheduled to play in the 1½ months between Wimbledon and the U.S. Open.

“I don’t think that affected me,” she said. “I don’t think it did. Maybe it did.”

She arrived at Flushing Meadows full of confidence, as usual, and said she didn’t need tuneup tournaments to get ready. While Williams’ thumb appeared fine, and there were no obvious injuries, her father said Sunday that she was dealing with other physical problems — and doing a “marvelous job of hiding it.”

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“It’s kind of like she had no energy. No get-up-and-go,” Williams’ mother, Oracene Price, said after the Henin match. “Tennis is a head game, sometimes. Your head tells you to do something, but you can’t.”

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