Novak Djokovic  admitted he is dealing with a number of physical problems after fighting off a terrific challenge from Alejandro Davidovich Fokina to reach the fourth round of the French Open for a 14th consecutive year.

The 7-6 (4) 7-6 (5) 6-2 victory took three hours and 36 minutes, with Djokovic twice a break down in the first set and forced to save a set point in the second.

The 22-time grand-slam champion looked unsettled in windy conditions, while he called the trainer before the third set to have his left thigh massaged, but, as he so often does, he found a way to come out on top.

Asked about the medical time-out, Djokovic said: “We don’t have much time to start to name the many injuries I have, and the list is quite long.

“I still kept on playing. These are the circumstances that you, as a professional athlete, have to deal with. Accept it. Sometimes you need help from (a) physio during the match. Sometimes you need pills. Sometimes you need help from the god or angels, or whoever.

“The reality for me nowadays is that my body is responding differently than it did a few years ago. I managed to finish the match.”

Djokovic, who again wore a nanotechnology device on his chest, had struggled in his opening set against Marton Fucsovics on Wednesday before breezing through the next two, and it quickly became clear Spaniard Davidovich Fokina would offer a real test.

The 23-year-old, ranked 34, saw a break for 3-2 swiftly erased but moved ahead again to lead 6-5 after Djokovic double-faulted three times and was given a time violation.

Again, Davidovich Fokina was unable to serve it out, though, and Djokovic made him pay for the wasted opportunities by winning a tie-break.

This time the challenge very much continued in the second set as the pair exchanged breaks of serve three times, with Djokovic unable to clinch it at 5-4.

Davidovich Fokina had one chance to level the match in Djokovic’s next service game but he could not take it and the Serbian again came out on top in a tie-break.

Alejandro Davidovich Fokina sits on the court after slipping
Alejandro Davidovich Fokina sits on the court after slipping (Christophe Ena/AP)

Djokovic let his emotions out, roaring and fist-pumping, but the toll the effort had taken became clear when he called the trainer, applying ice to his left thigh and gesturing sarcastically towards the crowd.

Djokovic looked distinctly uncomfortable at times in the third set but he forged ahead early on and did not let Davidovich Fokina back in, giving a weary celebration when the Spaniard’s resistance finally ran out.

“I knew that it’s going to be a very difficult match, a very physical match,” said Djokovic.

“He contested very, very well. He’s an amazing fighter, amazing player. Congratulations to him for fighting. Bad luck but he played a great match.

Lorenzo Sonego looks disbelieving after beating Andrey Rublev
Lorenzo Sonego, pictured, looks disbelieving after beating Andrey Rublev (Jean-Francois Badias/AP)

“Of course a win is a win, maybe a little bit too much, three hours for two sets. I thought, if I would lose the second set, we’d probably play for five hours.

“But you have to be ready. It takes a lot of effort but we all have to believe in ourselves. I’m proud of the performance today for sure.”

The behaviour of the crowd has come under the spotlight this week, with boos frequently ringing around Roland Garros.

Of his own reaction while he received treatment, Djokovic said: “I think the majority of the people come to enjoy tennis or support one or the other player. But there are people, groups or whatever, that love to boo every single thing you do.

“That’s something that I find disrespectful and I frankly don’t understand that. But it’s their right. They paid the ticket.

“Actually 99 per cent of the time I will stay quiet. Sometimes I will oppose that because I feel, when somebody is disrespectful, he or she deserves to have an answer to that.”

Djokovic could meet Carlos Alcaraz in the semi-finals, and the world number one had a much easier time in reaching round four, beating Denis Shapovalov 6-1 6-4 6-2.

Alcaraz was a break down in the second set but won five games in a row, and said afterwards: “I felt great, I think I played a great level the whole match.”

Carlos Alcaraz
Carlos Alcaraz had a comfortable win over Denis Shapovalov (Christophe Ena/AP)

It was another day of long matches, with Italian Lorenzo Sonego fighting back from two sets down to defeat seventh seed Andrey Rublev, while Austrian qualifier Sebastian Ofner saw off Fabio Fognini in five sets.

After his epic victory over Stan Wawrinka, Australia’s Thanasi Kokkinakis was involved in another lengthy battle with 11th seed Karen Khachanov but was unable to force a decider, losing 6-4 6-1 3-6 7-6 (5).

Russian Khachanov declined to answer questions about the war in Ukraine afterwards, saying: “I am a sportsman, I am not a politician. I don’t want to talk here about politics because, first of all, I am not good at it. And, second of all, it’s not my job.”