Top seed Agnieszka Radwanska eased into the semi-finals of the ASB Classic in Auckland with a 6-3 6-3 victory over Russia's Elena Vesnina.
A solitary break of serve was enough for Radwanska to take the opening set and, after a 90-minute rain delay early in the second, the Pole returned to break twice more and close out the match.
She will play the only remaining unseeded player, American Jamie Hampton, in the last four after Hampton outlasted Kiki Bertens of the Netherlands 6-1 6-7 (5/7) 6-2 in her quarter-final.
On the other side of the draw, third seed Yanina Wickmayer will take on eighth seed Mona Barthel in the last four.
Wickmayer overcame Kirsten Flipkens 6-3 6-3 in an all-Belgian battle that was disrupted three times by rain and finished with the umpire over-ruling a line call on match point.
Barthel romped to the quickest victory of the week; the German shrugged off an early service break to dispose of Swede Johanna Larsson 6-2 6-1 in 44 minutes.
"I'm playing really good tennis, and if I can play the same way (on Friday), I think I have a pretty good chance," said Barthel.