Petra Kvitova rallied to defeat Venus Williams 3-6, 6-3, 7-6 (2) and advance to the Pan Pacific Open final on Friday.
The seventh-seeded Kvitova won when Williams' return was long to close the match at Ariake Colosseum in 2 hours, 24 minutes.
Kvitova dominated the tiebreak, jumping out to 6-0. Williams pulled two points back before Kvitova capitalized on her third match point.
"I am really happy with how I played today," Kvitova said. "It was a very close match and every game was up and down."
Kvitova, who held off 11 break points, will face either fourth-seeded Caroline Wozniacki or fifth-seeded Angelique Kerber of Germany.
Williams was bidding for her first title since last October, when she won in Luxembourg.
"I was probably a little tired," said Williams, who endured a three-hour, three-setter on Thursday. "But I don't think it affected the match. She played two matches yesterday so no doubt was a little tired as well."