The former world men's tennis number one Marat Safin has withdrawn from the Queen's Club grasscourt tournament in London with a back injury.
The Russian, a semi-finalist at Wimbledon last year, had been due to play Belgium's Xavier Malisse after receiving a bye in the first round.
Frenchman Gael Monfils, the fourth seed, also withdrew with a wrist injury sustained during his second-round victory over Andrey Golubev on Wednesday.
Steve Darcis of Belgium, who had been the third round opponent of Monfils, advanced to the quarter-finals on a walkover.
