Nishikori retires injured, Khachanov to play Rublev in Halle

HALLE, Germany (AP) Third-seeded Kei Nishikori was forced to retire with an injury during his second-round match against Karen Khachanov at the Gerry Weber Open on Thursday.

The Japanese player was trailing 3-2 when he withdrew with a left hip problem.

Khachanov will next face Andrey Rublev in the quarterfinals. Rublev, who received a wild-card for the grass-court tournament, defeated Mikhail Youzhny 6-0, 3-6, 6-3.