OSAKA, Japan -- Defending champion Samantha Stosur advanced to the quarterfinals of the Japan Women's Open on Thursday when Jarmila Gajdosova retired with an injury while training 7-6 (4), 1-0.
The top-seeded Stosur will next face Yulia Putintseva of Kazakhstan.
Also, Zarina Diyas of Kazakhstan beat Lara Arruabarrena of Spain 6-0, 6-1, Lauren Davis of the United States defeated Japanese qualifier Shuko Aoyama 6-1, 6-1, and Ana Konjuh of Croatia beat fifth-seeded Coco Vandeweghe of the United States 6-2, 3-6, 6-3.