Top seed Venus Williams survived a second-set wobble to book a place in the AIG Japan Open final with a 6-3, 7-5 victory over Caroline Wozniacki on Friday.
Williams raced into a 4-0 lead in a first set never in doubt, but went 4-2 behind in the second to the 17-year-old Dane at Tokyo's Ariake Colosseum.
"Being 4-2 down is not the set," said Williams. "If you win one game it's pretty much even so I was just concentrating on not making any errors."
The Wimbledon champion will play No. 5 seed Virginie Razzano in the final Saturday.
France's Razzano beat Italy's Flavia Pennetta 4-6, 7-5, 6-3 in their last-four match.
Williams has won 19 of 21 matches since Wimbledon and victory last weekend at the Korea Open means she is in line for her second straight title and fourth of the season.
"It's been a while since two in a row," said Williams. "I'm thinking, 'Can I do this?' It's exciting."
Williams is looking to qualify for the season-ending Sony Ericsson championships.
The tournament brings together the top eight players on the WTA Tour and Williams currently sits eighth.
Meanwhile, David Ferrer, the men's top seed at the $175,000 tournament, advanced to the semifinals with a 6-4, 6-4 win over Feliciano Lopez.
Spain's Ferrer is looking to qualify for the season-ending Tennis Masters Cup in Shanghai. He sits sixth in the rankings for the tournament contested between the top eight players in the rankings.
Ferrer will meet seventh-seeded Ivo Karlovic in the semifinal after the Croatian beat Australia's Lleyton Hewitt 7-6 (7-5), 7-6 (8-6) in their last eight-eight match.
Karlovic hit 25 aces on the way to victory.