Sloane Stephens made it two wins in two games to lead the way in Red Group at the WTA Finals in Singapore, as she beat Kiki Bertens in three sets. The margins were tight with both players in with a chance of sealing their spot in the semi-finals. Stephens would have confirmed her place with a straight sets win, while Bertens - thanks to Angelique Kerber's three-set win over Naomi Osaka earlier - simply needed victory; however, neither occurred. The opening set was decided on a tie-break, which Stephens took 7-3. But Bertens turned things around in the second, opening up a 5-1 lead, and although Stephens saved four set points to claw a break back, the American lost the next game - and the set 6-2. From 2-0 down in the decider, Stephens won four games in a row - and broke Bertens again to complete a 7-6(4), 2-6, 6-3 win. The result makes for an intriguing last day in the round-robin phase with all four players in Red Group still able to qualify for the semi-finals.