Bulgarian qualifier Tsvetana Pironkova reached her first WTA final with a semi-final win over second seed Petra Kvitova at the Sydney International on Thursday.
The world number 107 defeated her second top-ten ranked opponent of the week in a 6-4 6-3 victory.
Pironkova, 26, will play fifth seed Angelique Kerber in Friday's final after the German left-hander mastered American Madison Keys 6-4, 6-2.
"It's definitely a milestone. This is something I've been dreaming about for a long time now and something that I've been missing, to go to the final or even have a title," Pironkova said.
"I have been here a few times before. I've been playing qualifying here and I actually never imagined getting to the final here."
Pironkova ranked as high as 31 in the world in 2010 following her Wimbledon semi-final appearance against Vera Zvonareva, and lost to Kvitova in the Wimbledon quarter-finals the following year.
The Bulgarian has now won seven matches to get to the Sydney final, and reached the semis after beating Italian third seed Sara Errani in straight sets.
"I've had some pains here and there. It's quite normal considering I've been playing for seven consecutive days now," Pironkova said.
"But these are not serious injuries. These are normal things that happen to you after so many matches. I've had them before. I know it's nothing to worry about too much."
Kvitova said Pironkova had proved a difficult opponent.
"She moved well on the court, every ball was in the court," the Czech world number six said.
"It was tough for me to make a winner because she moved in the baseline very well. This was hard for me to have short rallies.
"She served well and she was returning my serve pretty well."
Kerber's powerful double-handed backhand was again on top form during her win over Keys.
"I am trying to be more aggressive than some months ago and try to play my game plan from the first point, and it's working. So I think that's better than last year," Kerber said.