MANHATTAN BEACH, Calif. (AP) -- Martina Hingis is seeing a lot of the Williams sisters lately.

Having beaten Venus Williams last week in the TIG Classic final, Hingis takes on the younger Williams sister, Serena, in today's Acura Classic semifinals.

``She's a very dangerous player, but not as consistent as Venus yet,'' Hingis said. ``I beat Venus last week and I consider her the tougher of the two Williamses and she's also better in the rankings.''

Hingis, the second seed, advanced with a 6-7 (5-7), 6-3, 6-3 victory over No. 7 Barbara Schett of Austria in Friday's quarterfinals.

Lindsay Davenport, the top seed and defending champion, also struggled before beating Conchita Martinez 6-7 (4-7), 6-3, 6-2. She'll take on Julie Halard-Decugis of France, who surprised No. 3 Mary Pierce 7-5, 6-2.

``She has a big forehand, she's very quick. It's going to be a lot shorter points,'' Davenport said. ``I'm going to try to play my game against a hard hitter, try to be on the offensive first and not let her dictate the points.''

Martinez's game of angled shots and slice backhands has given Davenport fits over the years, with the Spaniard holding a 7-3 edge. Martinez won all four of their previous meetings on hardcourts, with her last loss to Davenport coming indoors two years ago.

``To win this match is a huge confidence booster,'' Davenport said. ``On paper it might not look like a big win, but for me it is.''

The match turned on a line call in the second set after Davenport lost the first-set tiebreaker.

Davenport led 4-3 with the game tied 30-all. She hit a forehand deep in the corner that the baseline judge called out before correcting himself. The chair umpire could have ordered the point to be replayed, but she gave it to Davenport to set up break point against Martinez.

``It looked like she was playing it anyway and missed it,'' Davenport said.

Davenport hit a forehand winner for a 5-3 lead and then served out the set. The call came when she was in the process of winning seven straight games.

Martinez protested furiously and was visibly angry as the third set began.

``Everything from then on was uphill for me,'' she said. ``That wasn't a winner. I got there. We should've played two balls.

``There were many bad calls over there. You have to get some good linesmen. They made some mistakes. That's terrible.''

Davenport didn't lose her serve in the second and third sets. She broke Martinez twice in building a 4-0 lead.

Schett led 5-3 and had a set point before Hingis hit a backhand winner in the corner to tie the opening set 6-6. Schett led 5-0 in the tiebreaker when Hingis began her rally.

Hingis hit consecutive forehand winners to close to 6-5, then sent a forehand long to lose the tiebreaker.

``I just tried to hang in there,'' she said. ``When I broke her to go up 3-1 in the second set, I started believing in getting the match turned around on my side.''

Schett broke Hingis with a backhand winner on the line to pull to 3-2, prompting Hingis to fling her racket across the court toward her chair on the changeover. Schett held serve for 3-3, then Hingis reeled off seven straight games to win the set 6-3 and take a 4-0 lead in the third.

``I wasn't aggressive. I tried to be, but I missed too much,'' Schett said. ``When you play against her, you know why she's number one because she's always playing better at the big points. She anticipates very well and she's always there.''