Martina Hingis hammered Maria Sharapova 6-3 6-1 in the pair's first meeting to reach the first final of her comeback at the Pan Pacific Open in Tokyo.
Hingis and Sharapova were meeting on court for the first time
The former world number one, tournament winner in 1997, 1999, 2000 and 2002, outplayed defending champion Sharapova.
"It feels good to be in the finals once again - I never thought I would make it this far," said Hingis, 25.
The Swiss will face second seed Elena Dementieva in Sunday's final after she beat Anastasia Myskina 6-4 3-6 6-4.
Hingis returned to the game last month, reaching the Australian Open last eight and winning the mixed doubles.
Her defeat of Sharapova was her first victory against a top-10 player since she started her comeback this season after three years off.
"Everybody has always been asking me which player you want to play and I always said 'Maria' because I've never played her and she's a great champion - she has won Wimbledon at such a young age," said Hingis.
"I didn't miss much on the key points and I put her under pressure. I couldn't ask for more, because Maria is a number four in the world.
"I knew I had to come up with a great game and I did."
Sharapova had a break point on her serve in every game in the second set, and when Hingis made it 2-1 and then 4-1 in successive Sharapova service games, the writing was on the wall.
Hingis sealed the win with a third consecutive break - without facing a single break point herself.
Sharapova said: "She was picking up the ball very early. She used the quickness of the court as the advantage and came up with some good shots.
"We had a battle until about three-all (in the first set), and then she broke me. After that she served two aces. She gained a lot of confidence.
"That's what happened, one or two points and the other person gains a lot of confidence from that."