Boris Becker has questioned whether Roger Federer is the greatest player of all-time.
Federer, a 17-time grand slam champion, is widely seen as the best tennis player in the history of the game.
But Becker has questioned whether the Swiss Maestro would have beaten the likes of Bjorn Borg and John McEnroe without the benefit of playing in an era where racket technology has progressed.
"Is Federer the best ever? I don't know," Becker told ESPN.
"You have to say he is the most successful player we have seen, but how can you decide for sure that he is the best ever? Comparing generations is tough, especially in tennis, even though Roger ticks many boxes as the greatest ever.
"Federer has 17 grand slams, the most ever. He has the most weeks at world No.1, which is an impressive record and clearly he has been an incredible player for many, many years. His level of consistency is maybe his most impressive quality.
"However, would he have beaten McEnroe when he was at his very best in the 1984 Wimbledon final using a very different type of racket to the one he has now? I doubt it.
"Would he have beaten Bjorn Borg at his very best when he was dominating at the French Open or Wimbledon? Again, I doubt it, but that is not to belittle Federer's achievements for one moment.
"The big difference is the racket technology these days. I started with a wooden racket and you simply could not do some of the things guys like Federer and Nadal have done in recent years using that type of equipment. It would not have been possible. So they would have had to adapt their styles.
"I would love to see Federer and [Rafael] Nadal play a match with a wooden racket and see how they get on. It was a very different sport when McEnroe and Borg did their thing, but clearly the guys winning the big tournaments now deserve to be respected.
"Roger is still very much here and I still believe he will stay around for some time. He has set the bar so very high in his career and everyone looks for the minor crack in his make-up. I'm amazed by his commitment to the game considering he has two kids, as that was one of the reasons I decided to quit my career."