Roger Federer's defeat was caused by age, says McEnroe

Seven-time Grand Slam winner John McEnroe commented on the defeat of Roger Federer before Grigor Dimitrov.

The Swiss player dealt with a back injury and McEnroe had a clear explanation.

"As you get older, you will have more days when you simply won't have it," said the American.

Brad Gilbert added: "Amazing Grigor came to the US Open losing 6-7 games, but he definitely kept playing hard in the gym and on the practice courts, amazing how things can change dramatically in a tournament and what a chance now for him."

Tracy Austin wrote: "Amazing moment of 'feeling good' for @GrigorDimitrov!

If Rafa wins, the Majors score would look like this.

Roger 20 Rafa 19 Novak 16. Get more bowel all the time. Once Novak and Stan were out, it seemed that he was possibly lining up to be a Nadal-Federer final. After their long rivalry, surprisingly Rafa and Roger have never played "

Federer still feels safe looking to the future: "If I think I'll have more opportunities," I don't have the crystal ball.

And you? Exactly. So we never know. I hope so, of course. I think it has still been a positive season. Disappointing now, but I'll go back up, I'll be fine. "