Novak Djokovic was booed off the court on what could potentially be his last visit to the Australian Open, after retiring from his semi-final against Alexander Zverev at the end of the first set.

The hostile reaction stemmed largely from shock. Djokovic had not called the trainer to the court, and there had been little indication – unless you had an eye for the finer details of the game – that he was in serious physical strife.

At the point of Djokovic’s retirement, he and Zverev had just ground their way through a long and closely balanced opening set, which was decided by the smallest possible margin when Djokovic netted a volley to lose the tie-break by seven points to five.

Then came the surprise. Rather than returning to his bench at the end of the set, Djokovic walked around the net-post and shook hands with Zverev. The fans now began to express their dissatisfaction, as they realised that their entertainment – and it had been good entertainment until this point – was at a sudden end after 81 minutes of tennis.

This was the only singles match in the session, so the supporters were devastated. As the booing grew louder, Djokovic turned around as he was about to walk through the tunnel that takes the players off Rod Laver Arena, held up both hands and gave a double-thumbs up to the crowd, before applauding them a couple of times. And then he was gone.

“I did everything I possibly can to manage the muscle tear that I had [in the upper leg since the previous match against Carlos Alcaraz],” said Djokovic, whose movement had been respectable apart from one revealing point at the end of the 12th game when he allowed Zverev to hit into the open court without trying to chase the ball down.

“Towards the end of that first set I just started feeling more and more pain,” Djokovic added. “It was too much to handle for me at that moment. Yeah, unfortunate ending, but I tried.

“If I won the first set, maybe I would try a few more games, half a set, maybe a set. I don’t know. It was getting worse and worse. I knew even if I won the first set, that it’s going to be a huge uphill battle for me to stay physically fit enough to stay with him in the rallies, you know, for another God knows what, two, three, four hours. I don’t think I had that, unfortunately, today in the tank.”

As Djokovic departed, Zverev called on the fans to show some appreciation for the 10-time champion of Melbourne Park. “Please, guys, don’t boo a player who leaves the court due to injury,” he said. “I know that everyone paid to be here and hopes to see a great five-set match. But you have to understand that Novak Djokovic has given his all to this sport for 20 years.

“There is no one I respect more on the tour than Novak. I have always been able to send him a message, call him when things were not going well. He has helped me a lot. Last year in Shanghai, when things were really not going well after the US Open, we talked for hours.”

Djokovic had not been able to practise during either of his two off-days since that thrilling four-set victory over Alcaraz. When he was asked about his increasing susceptibility to injuries – including the meniscus tear which forced him out of last year’s French Open – he seemed genuinely baffled, and made no mention of the fact that he will turn 38 in May.

“It is true that, you know, [I’m] getting injured quite a bit last few years,” said Djokovic. “I don’t know what exactly is the reason for that. Maybe several different factors. But I’ll keep going. I’ll keep striving to win more slams. And as long as I feel that I want to put up with all of this, I’ll be around.

“I actually thought I played really well [at this tournament], as well as I played the last 12 months, to be honest. I liked my chances if I was physically fit and ready to battle.”

Is there a chance that this could have been Djokovic’s final Australian Open? He was not making any firm predictions either way. “‘I’ll just have to see how the season goes,” he replied. “I want to keep going. But whether I’m going to have a revised schedule or not for the next year, I’m not sure.

“I normally like to come to Australia to play. I’ve had the biggest success in my career here. So if I’m fit, healthy, motivated, I don’t see a reason why I wouldn’t come. But there’s always a chance, yeah.”

Finally, Djokovic was asked about the prospects for his coaching collaboration with Andy Murray. Will they continue to work together once his injury has healed? He had little insight to offer on this point.

“We both were disappointed with what just happened, so we didn’t talk about the future steps. We are so fresh off the court.

“I’ll definitely have a chat with Andy and thank him for being here with me. You know, give him my feedback, which is, of course, positive, and see how he feels and we make the next step.

“We are still hot-headed and disappointed, so it’s kind of hard to switch the page and start talking about what the next steps are. You know, I think we both need to cool off a little bit and then we’ll have a chat.”