The Danish star got the chance to practice with the 22-time Grand Slam winner at the recent Six Kings Slam event in Saudia Arabia and thinks that the legend is still at a level where he could continue his career.

Rune told Tennis365: "Do I get inspiration from other players or do I just focus on myself? A bit of both.

"I think inspiration is important, but I always try to be a beast, whether it’s in training, in preparation or in a match, I always want to push myself.

"You get inspiration from players like [Novak] Djokovic or Rafa Nadal.

"I remember training with Rafa in Riyadh, and it’s surprising. This guy is almost retired and he trains with such intensity that you think: ‘You shouldn’t retire’.

"He’s had an incredible career and he’s achieved so much, it’s not for nothing that Rafa and Novak both give their all in every training session."

Nadal confirmed that he would retiring from the sport last month as he posted an emotional message on social media.

The Spaniard said: "Hello everyone. I’m here to let you know that I am retiring from professional tennis.

"The reality is that it has been some difficult years, these last two especially. I don’t think I have been able to play without limitations.

"It is obviously a difficult decision, one that has taken me some time to make.

"But, in this life, everything has a beginning and an end.

"And I think it’s the appropriate time to put an end to a career that has been long and much more successful than I could have ever imagined."