Czech Marie Bouzkova, the No 5 seed, advanced to the last four of the Prague Open by beating American Ann Li, the No 9 seed, 3-6, 6-3, 6-3 at the Sparta Prague Tennis Club on Thursday.
Bouzkova, ranked No 47, will face Czech Tereza Valentova next.
The Czech won against Italian lucky loser Lucrezia Stefanini (6-4, 6-4) and Chinese qualifier Xinyu Gao (6-0, 6-2) ahead of her victory.
Earlier in the tournament, Li, ranked No 67, won against Frenchwoman Leolia Jeanjean (6-4, 6-3) and Australian qualifier Astra Sharma (7-6 (1), 6-3).
Prague WTA 250, other last 8 results (Sparta Prague Tennis Club, clay, USD 275.094, most recent results first):
Xinyu Wang vs. Sara Bejlek
Linda Noskova vs. Katerina Siniakova
Tereza Valentova beat Jessika Ponchet (LL): 6-2, 6-0