Tereza Martincova won twice in Group B to move into the final of the LiveScore Cup in Prague.
The world number 133, who was only invited to play at short notice after Marketa Vondrousova pulled out, beat Kristyna Pliskova and Karolina Muchova in the round-robin exhibition tournament.
Martincova first defeated Pliskova 4-6 6-1 6-1 and then followed it up with a 5-7 6-4 6-3 win over Muchova to set up a match with the winner of Group A.
It is all still up for grabs in Group A after Wimbledon semi-finalist Barbora Strycova swept aside Katerina Siniakova 6-2 6-1. Pliskova beat Strycova on Wednesday and will player Martincova if she sees off Siniakova on Friday.