Wimbledon champion Venus Williams saved five match points as she came back to beat Patty Schnyder in the semi-finals of the Bank of the West Classic.
Third seed Schnyder looked set to seal her first victory over Williams when she led 6-5 in the second set.
But the Swiss player faltered as Williams broke back, won the tie-break and sealed a 2-6 7-6 (7-4) 6-2 win.
The second seed will play Kim Clijsters in the final after the Belgian beat Germany's Anna-Lena Groenefeld 6-4 6-0.
Groenefeld broke Clijsters' serve to lead 4-3 in the first set, but her hopes of springing a surprise faded fast as she lost the next nine games.
Williams and Clijsters have played eight times, with the American winning six.
"We play similar games. We're good at covering the court and hitting hard," said Williams.
"What's different is I'm able to play that game a little better, serve and return
better, run a few more balls down. I step up more."
Clijsters said: "She can raise her level even when she's not playing her
"You have to stay aggressive and not let her get back into matches because when she has to play great, she does."