The Serbian ace has been forced to pull out of Roland Garros after hurting his knee during his victory over Francisco Cerundolo and his former coach Becker thinks that it is "bad news" for the sport.

He told Eurosport Germany: "This is bad news for all Djokovic fans, and I'm one of them. You could almost guess it after the match against Cerundolo, which he played with a limp.

"The painkillers made the fifth set easier, but he had already warned that evening what the next morning would be like. He already had knee problems at the last few tournaments but never spoke about them.

"That's obviously very bitter for him. I wish him a speedy recovery so that he is fit again for the grass-court season."

The injury has raised doubts about Djokovic's participation at Wimbledon next month and Becker knows that it could take a long time to heal.

The pundit said: "It's a serious injury and it won't go away tomorrow. That leaves me a bit speechless.

"You need your knees on grass, you really do slip all the time. A torn medial meniscus is a serious injury and the question naturally arises as to whether surgery is necessary."

Becker continued: "Wimbledon starts in four weeks, then the Olympics in six, seven weeks. That's the worst possible time to have an injury. Especially such a bad one. There will now be a lot of discussion in the Djokovic camp about what the right treatment is.

"After an operation like that, if he needs one, you're on crutches at first, then you lose muscle. It takes weeks, if not months, before you have 100 per cent confidence in your knee again. It's a very difficult situation for Novak Djokovic."