Agnieszka Radwanska booked a Sydney International semi-final clash with Barbora Strycova thanks to a comfortable straight-sets win over Duan Ying-ying on Wednesday.
The second seed triumphed at this WTA Premier event four years ago and she is two wins away from another title after a straightforward 6-3 6-2 success.
The opening five games of the first set saw four breaks of serve as both women struggled to hold, but it was Radwanska who made the telling breakthrough in game eight.
She was forced to save another break point en route to serving out the set, but the second was one-way traffic as the Pole cruised through to meet Strycova, who edged out 10th seed Caroline Wozniacki 7-5 6-7 (6-8) 6-4.
The other semi-final sees sixth seed Johanna Konta take on Eugenie Bouchard, after both enjoyed straight-sets victories on Wednesday.
Daria Kasatkina had knocked out world number one Angelique Kerber in the previous round, but there was no repeat performance as Konta prevailed 6-3 7-5, while Bouchard ousted Anastasia Pavlyuchenkova 6-2 6-3.
Elsewhere, Risa Ozaki, Kiki Bertens, Lesia Tsurenko and Shelby Rogers all won through at the Hobart International to book their quarter-final berths.