Lucie Safarova will meet Karolina Pliskova in an all-Czech semi-final at the Prague Open after beating Hsieh Su-wei 7-6 (7-3) 7-5
Safarova had not tasted victory this season before returning to home soil for this event, but picked up her third of the competition by overcoming her opponent from Taiwan.
The world number 16 failed to serve out the set at 5-4 as Hsieh forced a tie-break, but the Czech stormed into a 6-2 lead before taking set point at the second time of asking.
After a late rain delay, Safarova returned without a loss of momentum and completed a deserved triumph by breaking her opponent.
Pliskova came out on top in her previous encounter with Safarova in Stuttgart last week and she booked her place in the last four in far more routine manner, the defending champion taking just 51 minutes to see off Camila Giorgi 6-2 6-1.
Top seed Svetlana Kuznetsova lost the first set to Monica Puig but fought back brilliantly to come out on top in a tightly contested match.
The Russian had to slog it out for two hours and 18 minutes in order to complete a 4-6 7-5 6-4 triumph.
Kuznetsova's semi-final opponent will be Samantha Stosur, who took even longer - just under three hours - to beat Barbora Strycova 6-3 6-7 (3-7) 7-6 (7-4).