'I don't have a crystal ball': Roger Federer unsure if he'll ever claim record 21st Grand Slam

Tennis great Roger Federer has won practically every trophy available in his outstanding career thus far but after crashing out of the US Open quarter-finals the Swiss is unsure if he'll win a record-extending 21st Grand Slam.

The 38-year-old third seed was beaten in five sets by Bulgaria's Grigor Dimitrov just weeks after losing the Wimbledon final to perennial rival Novak Djokovic, failing to convert two championship points in the process. And, as father time continues to tick forward, Federer has been left wondering if number 21 will ever come.

"I don't have the crystal ball. Do you?" Federer said when asked by a reporter if he can extend his record Grand Slam trophies. 

"We never know. I hope so, of course. I think still it’s been a positive season. Disappointing now, but I’ll get back up, I’ll be all right."

Despite the blow of losing out in Wimbledon while victory was within touching distance, Federer said that the disappointment of that July day in the All England Club didn't affect his performances at the Arthur Ashe Stadium.

"I didn't think of it. If you move on, it’s a thing of the past. I do remember playing good semis there, so it wasn’t bad. If I think of that, I’m, like, really happy," he said.

Federer will have to wait until early next year for his next Grand Slam opportunity at the Australian Open but even at his relatively advanced age (in sporting terms at least) as a packed schedule in his immediate future.

"Laver Cup, Shanghai, Basel, maybe Paris, London. That’s the schedule for now. I don’t know if the team have other ideas or not," said Federer. "I'm happy to get a bit of a break now, go back to practice, reassess and attack from there.

"(I have) got to take the losses. They’re part of the game. Looking forward to family time and all that stuff, so... Life’s all right."