Alison Riske defeated Chinese qualifier Wang Xinyu 6-3, 7-5 on Wednesday to set up an all-American semifinal against Danielle Collins at the Upper Austria Ladies Linz.
World No. 73 Riske is going into her second semifinal this year, after reaching the final in Portoroz, Slovenia in September.
She came back from 5-2 down in the second set to close out the win over Wang, who had upset U.S. Open champion Emma Raducanu in the previous round.
The third-seeded Collins, who is pursuing her third title of the season, beat Alison Van Uytvanck of Belgium 7-5, 6-3.
Collins, who is ranked No. 29, recovered from a break down to take the opening set against Van Uytvanck and won three games in a row in the second to wrap up the win.
Riske and Collins have played each other once before — in Rome in 2018, when Collins won in three close sets.
Simona Halep also advanced to the semifinals, rallying to beat Jasmine Paolini of Italy 4-6, 7-5, 6-0.
The former top-ranked Halep will play fellow Romanian Jaqueline Cristian, who defeated Veronika Kudermetova of Russia 6-3, 7-6, for a place in Friday’s final .