Roger Federer can keep on playing at the highest level for a number of years according to his former coach, Tony Roche.
At 33 Federer is the eldest player in ATP top 20, and is one of only two players inside the top ten who are over 30, the other being David Ferrer.
Despite this, Federer continues to match the best in the game, having enjoyed a strong 2014 campaign in which he claimed five titles and reached the final of Wimbledon and the semi-finals of the Australian Open and the US Open.
Roche is confident that Federer can continue to play at the highest level despite being a lot older than many of his competitors.
"I think he can play as long as he wants to on the mental side. Physically, I think he can play for another four-five years without any problem," said Roche.
The Australian believes that Federer's style of play is the key to his longevity as he does not take as much physical strain as some other players and therefore avoids frequent injuries.
"It's the way he hits the tennis ball so fluently it's not so physical as a lot of the other guys…" explained Roche.
"It's just the way he plays, he does not take much out of him. He is lucky to not have any serious injury over the years. Injuries play an important role in tennis. Look at Rafa (Nadal). He's got an unbelievable record but it could have been a lot better if he stayed healthy."
While Federer was there or thereabouts in all of this year's Grand Slams, he faces an uphill battle to add to his record 17 Grand Slam titles. For his part, Roche believes that the Swiss maestro is always in with a chance of winning titles.
"Another Slam definitely… Obviously, Wimbledon is his best chance but he's knocking on the door in last few Slams. As long as the guys still respect Roger, he is always going to be a threat," he said.