Belinda Bencic is on the verge of claiming the last spot at the season-ending WTA Finals after winning her Kremlin Cup quarter-final on Friday.
Bencic saved two set points in the opening-set tiebreak in beating Kirsten Flipkens 7-6 (10-8) 6-1.
The Swiss player’s hope of reaching the tour finals had earlier been given a boost when fellow contender Kiki Bertens was beaten 6-4 2-6 6-1 by Kristina Mladenovic.
If Bencic beats Mladenovic in the semi-finals on Saturday she will secure the eighth and final place ahead of Serena Williams at the October 27-November 3 tournament in Shenzhen, China.
Bertens now needs at least one player to withdraw to play in the tour finals.