STANFORD, Calif. — Kim Clijsters took a little something off her inconsistent serve and turned her focus to placement over pace.

One in particular, a perfect second serve down the middle, helped change her fortunes on a day Clijsters hardly had her best game.

The top-seeded Belgian overcame a rocky first set to beat Czech teen Nicole Vaidisova 7-5, 6-2 on Saturday to reach her fifth straight championship match at the Bank of the West Classic.

Clijsters will face second-seeded Patty Schnyder, a 7-6 (4), 6-1 winner over unseeded Tatiana Golovin in Saturday's late match to set up the first final between the top two seeds in two years.

Clijsters' timely ace in the 10th game allowed her to even the score at 5-all.

"I don't know what I was thinking," Clijsters said, smiling. "Sometimes it just comes into your mind. Without thinking about it, you do it. Sometimes that's better. There, I just decided to go for it. Lucky enough, it hit the line."

Clijsters and Schnyder haven't played since the 2005 Berlin Open, where Clijsters retired because of a knee injury. Schnyder is in her first final in this tournament and has never won a set from Clijsters on hardcourts.

"She's the defending champion, the defending U.S. Open champion," Schnyder said. "She's just on on hardcourt. I'll just try to play a good match. ... She gives you a hard time with all her strokes."

Schnyder, the left-hander ranked eighth in the world, is looking for her first tournament title this year. She held on after the 18-year-old Frenchwoman rallied from a 4-1 deficit in the first set to force a tiebreaker.

Schnyder didn't double fault once and found her rhythm on her backhand late in the first set after making several errors from that side early.

Clijsters struggled to find a groove on her serve and needed five set points before finally holding to take the first set, when seven of the games went the distance to deuce.

Suddenly having regained her confidence, she pumped her left fist as she headed into the changeover and proceeded to make quick work of Vaidisova — a French Open semifinalist this year — in the second set.

After a 52-minute opening set, the second lasted only 33 minutes. Vaidisova had as many or more problems with her own serve.

"She's a top player. She's had those situations many times before," Vaidisova said of Clijsters' second-serve ace. "I didn't stop playing because I got frustrated with my serve. She played well the whole time. I made some stupid errors and she took advantage of that."

Clijsters, the world's No. 2 player coming off her 400th career singles victory in Friday's quarterfinals against Vera Zvonareva, won her 11th consecutive match in this tournament and is seeking her second straight Bank of the West title and fourth overall. She hasn't lost in the tournament played on Stanford's campus since 2002.

After holding for 1-1 in the first set, Clijsters squandered five break point chances in the third game and then lost her next service game for a 3-1 deficit. That began a stretch of four straight service breaks.

Trailing 5-4, Clijsters hit a forehand long to fall behind 30-40 and give Vaidisova a set point. Clijsters then hit a first serve into the net before following with a 99 mph ace down the middle to get it back to deuce — giving her the huge momentum swing she needed. After Vaidisova's unforced error, Clijsters hit another ace to make it 5-5.

Vaidisova advanced to the semifinals without dropping a set, but the 17-year-old got down on herself late in the first set and sailed a forehand long on match point to end the first career meeting between the women, who practiced together earlier in the week.

"When you play those younger players ... from the start they have nothing to lose and it's like any other match for them," Clijsters said. "When it gets close, that's when experience can play a little bit of a role."

After losing the first game of the second set, Clijsters won 14 points in a row and three straight games at love.

Clijsters, who improved to 18-2 in this tournament and is trying for her 32nd career singles title, had all four of her double faults in the opening set. She missed this event in 2004 because of a wrist injury but won in '03 and last year.

"This has always been one of my favorite trips of the year," she said.