Novak Djokovic previously admitted that he would never be good friends with Rafael Nadal, due to the intense rivalry they shared over the years. Nadal announced his retirement from professional tennis on Thursday after winning 22 Grand Slam titles over a 23-year career.

In a post on social media, the 38-year-old 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.”

Nadal has had many battles over the years with Djokovic, who previously stated he could never be friends with the Spaniard due to the immense rivalry they shared. Speaking to Italian publication Corriere Della Sera at the time, the 37-year-old said: “Nadal is only a year older than me, we are both Geminis, at first we even went to dinner together, twice. But even with him, friendship is impossible.

“I have always respected and greatly admired him. Thanks to him and Federer, I grew up and became who I am. This will unite us forever; therefore I feel gratitude towards them. Nadal is a part of my life, in the last fifteen years I’ve seen more of him than my mum!

“We have never been friends. Between rivals, it is not possible, but we have never been enemies. I’ve always had respect for Federer, he was one of the greatest of all time. He had an extraordinary impact, but I’ve never been close to him.”

Djokovic also spoke about how his rival Nadal would “inspire” him during his career, due to his ability to fight back from a negative place and secure victory. Appearing on Tennis Honors, the Serbian said: “So we go back a very, very long time. There’s a lot of things that inspire me in his career.

“Definitely the tenacity, dedication, fighting spirit. This kind of champions mentality of never giving up and always, in the face of adversity, finding a way to win, finding a way to come back. That’s a kind of a mentality that he posseses, that I find really inspiring.

“The intensity he brings out on the court makes you and requires you to really be at your top. Particularly when you are playing on clay. He thrives on that surface so much and it’s a real struggle, you know, facing him. He has left a legacy and a mark that is eternal in this sport.”

What is clear is that the pair have an enormous respect for one another, with Nadal previously having claimed Djokovic was the best tennis player in history. Likewise, the Serb showered praise on his rival after the French Open earlier this year.

He said: “He has been the greatest rival that I ever had. Matches against him on clay have frustrated me so much in my career, but they also made me a better player, made me understand what it takes to try to surpass him; try to win at least once or twice at Roland-Garros.

“It’s the highest mountain to climb for me to win Roland-Garros, particularly because of Nadal, because I always have to win against him in order to get to the title. We had some really fantastic matches here.”

Nadal has a whopping 22 Grand Slam honours – including 14 French Opens, two Wimbledon titles, four US Opens and two Australian Opens. Only Djokovic has more singles wins in major tournaments than the Spaniard.

Djokovic has secured 24 Grand Slam titles in his career – 10 Australian Opens, three French Opens, seven Wimbledon titles and four US Opens – and has won some of these majors against the great Nadal himself.

While Djokovic is yet to announce any plans for retirement, his great rival and fellow athlete Nadal will bid goodbye to the tennis world – leaving behind a legacy that makes sure that the sport will never be the same without him.