Yulia Putintseva's dream week at the St Petersburg Ladies Trophy continued as she fought from a set down to defeat Dominika Cibulkova and reach the final.
The world number 34 reached her first WTA Premier level semi-final by defeating home favourite Svetlana Kuznetsova in the last eight and has now gone one better with a 3-6 6-4 6-4 victory over the second seed.
Cibulkova, last year's WTA Finals champion, appeared on course for victory after breaking for a 3-2 lead in the deciding set.
However, Putintseva fought back to level and Cibulkova wilted when serving to stay in the match at 5-4 down.
Standing in her way of victory is another surprise finalist in Kristina Mladenovic, who saw off plucky wildcard Natalia Vikhlyantseva.
The Frenchwoman deposed reigning champion Roberta Vinci on Friday, but was staring down the barrel of defeat as the unfancied Russian - ranked 115th - took the first set.
However, Mladenovic - who had accounted for Venus Williams earlier in the tournament - fought back to record a 4-6 6-2 6-2 win in just under two hours and 10 minutes.