Veronika Kudermetova saved five set points against Danielle Collins to reach the Adelaide International 2 semi-finals before Belinda Bencic eliminated Caroline Garcia.
On Thursday, sixth seed Kudermetova defeated American Collins 4-6 7-6 (7-5) 6-1.
Kudermetova saved five match points while serving to stay in the tournament at 6-5 down in the second set, forcing a tie-break.
Collins, who finished second to Ash Barty in the Australian Open final last year, seized a 3-0 lead in the breaker, but her Russian opponent rallied to tie the match.
The world number nine controlled the deciding set to book a clash with Bencic in the final four.
Eighth seed Bencic got the better of WTA Finals champion Garcia 6-2 3-6 6-4.
Garcia broke straight back after going 3-1 down in the final set, but Bencic broke for the fourth time in the match to go through.
Paula Badosa and Daria Kasatkina will contest the other semi-final after beating Beatriz Haddad Maia and Petra Kvitova respectively.
Elisabetta Cocciaretto saved two match points as she came from a set down to beat Bernarda Pera 5-7 7-6 (10-8) 6-4 in the quarter-finals of the Hobart International.
The 21-year-old Italian will now face 2020 Australian Open champion Sofia Kenin, who also stormed back to defeat Anhelina Kalinina 4-6 6-3 6-1.
Lauren Davis and Anna Blinkova will do battle in the other semi-final following wins over Wang Xinyu and Yulia Putintseva respectively.