LONDON (AP) — Andy Roddick reached the quarterfinals at Queen's Club on Thursday when fellow American Mardy Fish withdrew with a left ankle injury after losing the opening set 7-6 (5).

Top seeds Rafael Nadal and Novak Djokovic also reached the quarterfinals despite some struggles.

Fish fell on a slippery surface and got treatment on his ankle before deciding to stop.

"It's just unfortunate," Roddick said. "You know, for a number of reasons. Obviously, Mardy is a friend. I don't want him to be hurt."