Mary Pierce edged out world number one Lindsay Davenport 7-6 (7-5) 7-6 (8-6) to reach the WTA Championships final. Davenport recovered from 5-2 down in the opener to force a tie-break, which the world number five clinched thanks to a fortunate net cord.
There were no breaks of serve in the second but the American mishit two easy forehands to hand Pierce the match.
Pierce, 30, will now meet fellow Frenchwoman Amelie Mauresmo, who beat Russian Maria Sharapova 7-6 (7-1) 6-3.
Mauresmo had to rally after falling behind an early break against Sharapova, who began to feel some twinges of pain in the right shoulder injury that has dogged her for months.
The Russian made four straight forehand errors and also came up wuth a double-fault to hand Mauresmo the tie-break.
From then on, the Frenchwoman dominated.
"The tie-break was just a big giveaway. From then on, it was downhill," said Sharapova.
"When you are not physically 100%, it is really difficult to play, especially when the same injury keeps coming back.
 | When you are not physically 100%, it is really difficult to play |
"I think without the injury I was playing great tennis. And I felt like I was in control, so that still gives me a lot of confidence for next year."
Pierce, the French and US Open finalist, is continuing her return to form this season with a fine run in Los Angeles.
She reached the final undefeated after a perfect series of round-robin matches.
"I am very proud of myself for the year I have had, especially since Roland Garros," she said.
"There's just one more match this year, and I'm going to give it everything that I have."