Roger Federer
Federer poses with the Australian Open trophy Getty

Tennis legend Rod Laver believes there is one thing that separates Roger Federer apart from the likes of Rafael Nadal, Novak Djokovic, Andy Murray and the rest of the Tour.

Federer won his 20th Grand Slam when he defeated Marin Cilic in five sets on Sunday (28 January) to win the 2018 Australian Open and further cement his status as arguably the greatest tennis player of all time.

It continues what has been an unimaginable last 12 months so far as the 36-year-old defied injuries and age to enjoy a major career renaissance.

Federer began his resurgence with the 2017 Australian Open before going on to win a record eighth Wimbledon title. In total, he ended the year with seven titles and has already begun 2018 with a bang after his victory in Melbourne last weekend.

"He's certainly playing as well as he did eight or 10 years ago," Laver told AAP via Tennis World USA.

"I wouldn't say he's better but Roger is playing some of his best tennis. Not all the time maybe. But pretty close to all the time."

Federer's achievements are all the more admirable given his age and how he was written off many years ago. Statistical website FiveThirtyEight even predicted in 2014 that there would only be a 0.8% chance of the Swiss ace surpassing 20 Grand Slams.

Laver believes Federer's success comes from the fact that he is playing smarter as well as adapting to each of his opponents. "He's playing smarter," Laver noted. "You learn when you're playing an opponent or you see him a lot, he sees weaknesses that other people don't see.

"That's the difference between Roger and the field. The rest plays their game. That's a big advantage. He's enjoying it more. It's another edge. When he's hitting a backhand down the line, if he sees that happening still that will keep him going for another year."

Federer is still sitting in second in the ATP tennis rankings and is just 155 points behind current world number one Nadal.