Tony Roche is confident Roger Federer still has much to give to tennis despite being in the latter stages of his career and believes the Swiss ace's decision to change to a racket with a bigger head has helped him get back to his best.

The Australian, a 13-time men's doubles Grand Slam winner, coached the current world number two between 2005 and 2007. During their time together, Federer won eight Grand Slam titles while also losing in two major finals — both against Rafael Nadal at the French Open.

Federer came into the 2017 season after a six-month absence due to a knee injury. He was ranked number 18 in the world and had not won a Slam title since 2012. There were questions raised about his future in the game owing to his struggles to challenge for the major titles.

The 36-year-old silenced his critics by winning seven titles and rising to world number two by the end of the year and he has continued the form in 2018, winning the Australian Open in January this year. He has the chance to become the world number one for the first time since 2012 if he makes the semi-finals at the Rotterdam Open beginning on Monday (12 February).

Roche, who has coached a number of former world number one's including Pete Sampras and Pat Rafter, believes Federer changing his racket three years back has majorly helped him in winning matches and the Australian is not the first to make that observation.

Moreover, another reason for Federer's longevity at the top of the sport is due to the lack of injuries during his career. And Roche made it clear that it was not luck but the Swiss tennis legend's style of play that has kept him injury free. The 20-time men's singles Grand Slam winner has a very fluent style of play which does not take too much of a toll on his body as compared to Nadal, who has a very aggressive style that has taken a toll on his knee in the long run.

"I just tried to instil in Roger that to win slams, obviously, you got to win seven matches and sometimes you gotta win in five (sets)," Roche said, as quoted by Tennis World USA.

"Not being in great form shouldn't be an excuse. Our practice sessions were pretty full on and I like to think he enjoyed that, he didn't complain.

"Why not? I think last year, some of the matches that he's played, were some of the best matches he's played. He made a really smart move changing to a larger racquet — that helped him," the well-respected Australian coach explained.

"Look, Roger's not lucky, but to go through your tennis career and not have major injuries is a testament to the way he plays. Roger doesn't take anything out of himself with the way he plays."

Roger Federer
Tony Roche (R) coached Roger Federer between 2005 and 2007 Getty