Kei Nishikori retires injured from Wimbledon warm-up in Halle

Olympic bronze medallist Kei Nishikori had hip treatment courtside but in the end was forced to concede defeat.

Japan's Kei Nishikori returns a shot to Russia's Karen Khachanov during their match at the Gerry Weber Open tennis tournament. | ap 

HALLE: Japanese world number nine Kei Nishikori was forced to retire injured in the second round of the Wimbledon warm-up tournament in Halle on Thursday.

Nishikori, seeded third in the grasscourt tournament, was trailing 3-2 to Russia's Karen Khachanov when he felt a pain in his hip.

The 27-year-old Olympic bronze medallist had hip treatment courtside but in the end was forced to concede defeat.

Wimbledon gets underway on July 3 in London.