NEW YORK(AP) Kim Clijsters has upset Serena Williams in a U.S. Open semifinal that ended when the defending champion was docked a point for yelling at an official who called a foot fault.

The unseeded, unranked Clijsters reached the final by beating No. 2 Williams 6-4, 7-5 Saturday night.

With Williams serving at 5-6, 15-30 in the second set, she faulted on her first serve. On the second, the line judge called a foot fault, making it a double-fault. That made the score 15-40, giving Clijsters a match point. Williams went over and said something to the line judge, who reported it to the chair umpire. That led to the chair umpire awarding a point to Clijsters, ending the match.

Williams already had been given a code violation warning when she broke her racket after losing the first set.