Kei Nishikori has been forced to retire from the Japan Open after suffering a buttocks injury during his second-round match with Joao Sousa.
The 26-year-old - a two-time winner of the tournament in Tokyo - was 4-3 up in the first set when he made the decision to withdraw from the contest.
"It was hugely disappointing to have to retire from my match," Nishikori told reporters at a press conference afterwards.
"It is possible that the injury was due to an accumulation of fatigue and stress, but I came into this tournament with a lot of rest and feeling very ready. I will get examined and hope to recover in time for my next tournament."
Nishikori's withdrawal leaves second seed Gael Monfils as the bookies' favourite to win the tournament.
Written by
Neil Wilkes
Neil Wilkes
