Germany’s Angelique Kerber claimed the eighth and final place for the season-ending WTA Championship in Istanbul by reaching the Linz semi-finals on Friday.

Kerber, the world No.10, made sure of her place in the October 22-27 event by beating Austria’s Patricia Mayr-Achleitner 6-3 6-1.

She joins Serena Williams, Victoria Azarenka, Agnieska Radwanska, Li Na, Petra Kvitova, Sara Errani and Jelena Jankovic in the WTA showpiece tournament.

American Sloane Stephens saw her hopes of playing in Turkey dashed when she lost to Switzerland’s Stefanie Voegele, 6-7 (3-7) 6-4 7-5 in her quarter-final in Linz.