Kei Nishikori retires injured at Halle Open as Wimbledon looms

Kei Nishikori needed to take a medical time-out to treat a back injury before playing on for a few points and retiring with the score at 3-2 in the first set.

World number nine Kei Nishikori’s Wimbledon preparations suffered a setback on Thursday when he was forced to retire injured from his Halle Open round of 16 match against Russian Karen Khatchanov.

Kei Nishikori reacts during his quarter final match against Great Britain's Andy Murray. (REUTERS)

The third seed needed to take a medical time-out to treat a back injury before playing on for a few points and retiring with the score at 3-2 in the first set for the Russian.

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Wimbledon, the only grand slam to be played on grass, starts on July 3.

Khachanov will now play the winner of the match between fellow Russians Mikhail Youzhny and Andrey Rublev.