Tennis legend Rod Laver believes Roger Federer and Rafael Nadal are able to consistently achieve success despite passing years because the veterans are able to find motivation by "enjoying the sport" more than ever.

Laver also opined Federer is playing his best tennis at 36 while heaping praise the 20-time Grand Slam champion's improved backhand and "great volleying ability".

Federer was written off by quite a few of his critics when he suffered a four-year Grand Slam drought between 2013 and 2016. Greats from the previous generation, including Boris Becker, Pete Sampras, and Stefan Edberg had retired from the sport in their early 30s but the Swiss great kept extending his career without much success during the four-year period.

On the other hand, injury-prone Nadal form drastically dipped after his French Open win in 2014. Questions were asked of the Spaniard's title-winning abilities as he had struggled to go past the quarter-final stages of majors between 2015 and 2016.

'They're enjoying the sport so much more'

However, both Nadal and Federer defied the odds and contested in the final of Australian Open 2017 — a five-set marathon that was won by the latter. Notably, the two contemporaries had cut-short their 2016 seasons in order to recover from their respective injury concerns.

Since January 2016, Federer and Nadal have shared 15 titles between them, including the four Grand Slams last year. The former started his 2018 season on a high by defending his Australian Open title without breaking a sweat.

"Well, I think a lot of it is the fact that they love the game, they love the competition. Yes, they may not be playing as many tournaments as they did when they were younger, but they're enjoying the sport so much more," Laver was quoted as saying by during the launch of 2018 Laver Cup last week.

Roger Federer and Rafael Nadal
File photo of Roger Federer (L) and Rafael Nadal.Lintao Zhang/Getty Images

He added: "I look at Nadal and someone like Roger Federer, who at 36, sometimes I look at and think about eight or nine years ago, I'm not sure he was playing this well.

"He's got a different backhand, he's got great volleying ability now, and all of a sudden, it seems to me he's just enjoying every moment that he's on the court, and it's not a chore at all.

"And I think tennis needs that. I think it's nice that you look at Federer and Nadal, who say, 'Hey, I'm still enjoying this sport, so why should I give it up?'."

Federer, who has decided to skip the whole of the clay-court season, will lose his no. 1 spot to Nadal when the ATP Rankings are updated in April as he crashed out of the ongoing Miami Masters 1000 tournament as early as in the second round.

Nonetheless, Federer and Nadal are well ahead of the chasing pack on the ATP charts. For instance, third-ranked Marin Cilic is 4465 points behind second-placed Nadal.

Also, the likes of Novak Djokovic, Andy Murray, and Stanislas Wawrinka, who are part of the "big five", are struggling to return to dominant form following a series of injury concerns over the last 15 months.