Andy Roddick has told Rafael Nadal he must accept having to play through pain in defence of his Wimbledon title.

Roddick, through to the last 16 of the Aegon Championships, has been suffering from the same knee tendinitis that forced Nadal to pull out of the Queen's Club tournament.

He said: "I've had tendinitis for years and years. It's a fancy term for overuse. It's uncomfortable and painful but it's not something that's career-threatening if you play on it."

Nadal claims he has been playing in pain for some months and that he won't go on Centre Court if he is "not 100 per cent ready to play". But Roddick expects the Spaniard to be at the grand slam, which starts on 22 June. He said: "I don't think that I ever thought Nadal's Wimbledon defence was in jeopardy."

World No2 Roger Federer, meanwhile, has withdrawn from this week's Gerry Weber Open in Halle, claiming he is still feeling the effects of his emotional maiden French Open triumph on Sunday.

The Swiss star's victory over Robin Soderling saw him earn a record-equalling 14th grand slam title and he said: "I still feel exhausted by the incredible events of the past few days.

"It is hard for me to admit but I simply cannot imagine giving my best effort in another tournament right away."