A confident Sloane Stephens stormed into a semi slot at the WTA Finals with a convincing straight sets victory against top seed Angelique Kerber yesterday, joining fellow debutant Kiki Bertens in the knockout stage.

The former US Open champ continued her unbeaten run in Singapore with a 6-3, 6-3 triumph, her fifth straight-sets victory in a row over Kerber. After topping Red Group, Stephens will play Czech Karolina Pliskova in the semi-finals. For the first time since 2003, none of the top four seeds advanced to the semi-finals of the WTA Finals.