Novak Djokovic has admitted that he has been increasingly questioning the purpose of playing tennis. The world No. 1 cast doubts over whether he’d be able to continue his French Open campaign on Monday night after picking up an injury during his fourth-round match.

With his Roland Garros fate now uncertain, the 24-time Grand Slam champion has also addressed when he would “call it a day”.

Djokovic recently turned 37 and holds almost every record in the sport, making it more difficult to keep motivating himself. After playing more than nine hours of tennis across two rounds, he explained where he was at with his career.

“I play an individual sport, there is nobody who can substitute me. I need to show up at my best on a daily basis in every practice, not to miss one round of treatments, and I have to motivate myself consistently,” the reigning French Open champion told Tennis Majors.

Although he had plenty of support from fans and loved ones, Djokovic said he needed to find the real motivation from himself. He added: “After all these years and everything that I’ve achieved, it’s not easy to get up every day with the same clarity and desire to do certain things for the millionth time.

“On the other hand, I really love all of that, I enjoy it, it’s not a cliche, it’s a strong emotion, I’ve told you guys already. Apart from that, lot of things have to come together - both personally and professionally - in order for this level to be sustained for this long.”

After spending more than two decades on the tour, the Serb admitted that he was questioning his goals and motivation more often at this stage. “It’s all about the attitude - do I want something, what’s the purpose, what are the goals, do I really want this, or someone else wants it and I am just following along… These are the questions swirling around my head more frequently than before,” he explained.

But there is no danger of Djokovic ending his career for now. After playing a four-hour and 29-minute match in the third round and a four-hour and 39-minute contest in the fourth, he confessed he was still enjoying the battles on the biggest stages.

The world No. 1 continued: “But these kind of moments, these matches are what my dreams are made of, they inspire me: five sets with 10-15 years younger opponents in the greatest stadiums in the world, and me showing that I still have what it takes, that I am still able to physically outlast them.