Rafael Nadal and Roger Federer have been the constant talk of the tennis world in 2017, and have deserved all the space in TV news channels, newspapers and magazines.

There is a good reason or it: Both the former world number 1s have been in prolific form this season.

Though Nadal withdrew midway into the Paris Masters due to a knee injury, the Spaniard's chance of playing in the ATP World Tour Final in London has increased after the injury has not been deemed as serious as first feared.

Federer will come into the competition even more refreshed after skipping the Paris Masters.

Both Nadal — if he plays — and Federer will have their eyes in the upcoming ATP World Tour Final in London.

Experts and pundits have already outlined them as favourites for the ATP World Tour.

No one would disagree, as Federer won the Australian Open and Wimbledon while Nadal clinched French and US Open.

They have looked dangerous in big events, and both would love to end the year on a high as well.

The year might not have come to an end, but some former players like Greg Rusedski have already predicted about next season and their future.

"I can see Roger getting to 20, 21 by the end of next year possibly and Rafa is going to win a few more French's, so it will be very, very close. I think he's got one or two more left in him, Roger, if he can stay healthy — that's the big question. Also Rafa as well, how many years can he take this physical punishment? At any time their careers could stop because 30+ is all extra time," Rusedski told Sky Sports.

Federer Nadal

Class exists, but how will their body respond?

If one followed the 2017 season closely, both Nadal and Federer showed they are still world-class players. They played some astounding tennis.

However, one aspect that has been constantly talked about is their ailing bodies.

Nadal has had an injury-prone career, while Federer is 36, but both players have a few years left in them.

Expect the two players to give their best and entertain fans till their bodies decide to it quits, which may be in one, two or three years.