MANHATTAN BEACH, Calif. (AP) -- Serena Williams, blasting serves and charging down nearly out-of-reach balls, upset Martina Hingis 6-3, 7-5 in the Acura Classic semifinals Saturday night.

No. 1 seed Lindsay Davenport also was upset, losing 6-3, 7-5 to Julie Halard-Decugis of France as both of the world's top two players were beaten on the same day.

Williams, the sixth seed, took out the world's top-ranked player in just over an hour for her second career win over Hingis in five meetings.

``She surprised me. She played very well, attacked and didn't miss anything,'' said Hingis, who beat Venus Williams for the TIG Classic title last week. ``It's kind of depressing. You get in good position and she would just bounce back and hit a winner.''

Williams established a powerful presence from the start, serving a love game to open the match. She gained the set's only service break in the fourth game with a crosscourt backhand winner for a 4-1 lead.

``My plan was to make sure I stayed focused the whole time and make the shots I'm supposed to make and not lose concentration,'' Williams said.

Williams faced the only two break points on her serve in the seventh game, but she aced Hingis, who missed a forehand long to reach deuce. Williams got a bit lucky with a forehand off the net cord for the advantage and served one of her seven aces for a 5-2 lead.

The players stayed on serve in the second until Williams earned the only break for a 6-5 lead.

Leading 30-15, Williams was on the run from side to side when she chased down a ball in the corner, hit a backhand and Hingis dumped the ball into the net. Williams broke on Hingis' wide backhand.

``There are very few people who can get the ball by me,'' said Williams, who lost to Hingis in last year's Acura quarterfinals.

Williams is playing her first singles tournament since June. A day earlier, the second-seeded Hingis said she considered Venus the tougher and more consistent of the sisters. The loss didn't change her mind.

``She doesn't play like this every day, otherwise she would be the better one than Venus,'' Hingis said. ``Serena is all pumped up this tournament. She came in all fresh and pumped. She was quicker than me, always a step ahead.''

Williams trailed 30-15 on her serve in the final game before hitting three consecutive winners to set up match point. She put a ball deep to Hingis' backhand and the Swiss teen-ager could only make a feeble swat at the ball.

``A more younger Serena would probably have lost serve at the end of the match, several times during the match and probably would have got upset and maybe even thrown her racket,'' the 17-year-old said. ``But fortunately enough I've eradicated that Serena and she's out of here.''

Williams hit 36 winners to just eight for Hingis.

``There's not much I could have done better,'' Hingis said.

Davenport committed 32 unforced errors in losing to Halard-Decugis, a player she had beaten in five of six previous meetings.

``I was awful,'' said Davenport, who defeated Halard-Decugis 6-0, 6-4 on the way to winning last year's Acura title. ``It was just kind of a weird day.''

Most of Davenport's errors came on her forehand, a usually trusty weapon in her powerful game.

She had two break points when Halard-Decugis served for the first set, but hit two forehands wide and then missed two more to drop the set. Halard-Decugis lost just eight points on her serve in the set.

``I missed four forehands in the fence, not even close, and you can't do that. You've got to make balls in,'' she said. ``I didn't feel like I was doing that at all. I had problems getting over to the ball and just using too much arm.''

Halard-Decugis, ranked 16th in the world, has won titles at Auckland, New Zealand and Birmingham, England this year. She beat recently retired Steff Graf in three sets in the German Open in May.

``She's a great player and I'm very happy to beat her,'' Halard-Decugis said of Davenport, the top seed and world No. 2.

Halard-Decugis surprised third-seeded Mary Pierce in Friday's quarterfinals.

``I heard she played pretty well against Pierce, but Pierce made a lot of errors and I did the same thing,'' Davenport said.

Davenport aced Halard-Decugis to take a 5-2 lead in the second set. The Frenchwoman committed three double faults in the next game, but Davenport couldn't get a break point. Her forehand shot hit the net cord and landed wide.

``It's so bad not to break if the girl doubles three times and is sitting on second serves,'' Davenport said. ``I wasn't even getting the balls back in. I was making dumb errors.''

Halard-Decugis won the final five games, including breaking Davenport on a double fault for a 5-4 lead.

``I was going for my shots. I held my serve very well,'' Halard-Decugis said. ``She has a very tough serve, one of the best on the tour. I was trying to put the ball in the court. I just went for it.''

After Halard-Decugis dispatched Pierce in a day match Friday, Davenport struggled to beat Conchita Martinez in three sets at night. She played Saturday's match with her left hamstring wrapped after pulling it slightly against Martinez.

Davenport lost in last week's semifinals at Carlsbad against Venus Williams. She has one more tournament scheduled before beginning defense of her U.S. Open title later this month.

``This spring I didn't play that well and you never know when it turns around. For me it just turned around at Wimbledon,'' said Davenport, who beat Graf on the grass for her second Grand Slam title.