Magnus Norman has pinpointed two reasons for Roger Federer turning the clock back and regaining his best form in 2017 despite being one of the oldest players on the ATP Tour.

Questions were raised about the 36-year-old's future in the game after he was struck down by a knee injury that forced him to miss the last five months of the 2016 campaign. Moreover, he had not won a Grand Slam since 2012.

Federer silenced his critics by winning three of the first four tournaments he entered in 2017 which included the Australian Open and two Masters Series titles in Indian Wells and Miami. The Swiss ace followed it up with four more titles at Halle, Wimbledon, Shanghai and Basel.

The 19-time Grand Slam champion started the year ranked number 17 in the world and seven titles later he is now ranked number two, just 1040-points behind long-time rival Rafael Nadal, who also had a stellar year after an injury-plagued 2016 campaign.

Federer bounced back and displayed a new aggressive form of tennis, but his "fitness first" mantra is something that allowed him to be competitive in every event he entered. He played a limited schedule entering just 17 tournaments, the fewest among the current top four, but lost just five times in 57 matches.

Norman has praised Federer's commitment and believes the Swiss star has shown the younger players and the likes of Novak Djokovic, Andy Murray, Stan Wawrinka and Milos Raonic, who are returning from injury, that one can be competitive at any point during their careers be it the prime or the latter stages.

"Roger showed you can be very competitive at 35 if you are excited and committed," the player-turned-coach Norman said, as quoted by the Express.

Roger Federer
Roger Federer ended the year as the world number two after winning seven titles including two Grand Slams Getty