Novak Djokovic fought off a hamstring injury and Carlos Alcaraz to reach his 12th Australian Open semi-final - and then claimed he was worried he would not be fit to play on Friday.

But both the Spaniard and John McEnroe questioned the seriousness of the Serbian superstar’s latest ailment.

In a night of high drama in the Rod Laver Arena, the 10-time champion here suffered an early hamstring strain and took a medical timeout to get his thigh strapped and take painkillers.

And despite losing the first set and limping throughout the rest of the contest, the Olympic champion showed his warrior mentality to win 4-6 6-4 6-3 6-4.

He took his first match point at 12.57am local time to keep alive his bid to win a record 25th Grand Slam singles title. After outlasting the 21-year-old Alcaraz, the Olympic champion then shared an emotional hug with his coach and fellow 37-year-old Andy Murray at the end of the contest.

After getting an apology from Channel Nine over "insulting and offensive” comments, Djokovic ended his post-match interview boycott on the court. When Jim Courier asked him how he had managed to win, the Serb said: “With my two legs and two arms, I guess. Well, one and a half legs.”

He is now set to face world No.2 Alexander Zverev. But speaking in his post-match press conference, Djokovic said the injury was “very similar” to the three centimetre tear in his left hamstring injury he suffered on his way to the title in 2023.

“If I had lost the second set, I don’t know if I would have continued playing,” he said.

“Now it's really about recovery. I'll take it day by day. I'm concerned. I am, to be honest, physically. The doctor gave me some painkillers. That kicked in after 20, 30 minutes. It did help. Then I had to take another dose I think in the beginning of the fourth. Now that it's cooling off, I can start to feel different things. Let's see how it goes tomorrow and day by day.

“But if I manage somehow to be physically good enough, I think mentally, emotionally I'm as motivated as I can be.”

Djokovic, who pulled out of last year’s French Open with a meniscus tear in his right knee, smiled: “I don't recall last time it was any Slam without some form of drama, to be honest.” But McEnroe cast doubt on the injury during his TV commentary by saying: “This isn’t the first time we’ve seen this routine. Don’t be fooled.”

Reigning French and Wimbledon Alcaraz, who was seeking the final leg of a career Grand Slam, admitted he had been distracted by Djokovic’s injury. “I'm not saying he made a show,” said the Spaniard. “It's obvious and everybody saw it that he's struggling in the second set. Then in the third and fourth set he showed he was really good. when you seeing someone that is struggling physically a little bit, you are not playing the same level.”

Djokovic said his hug with Murray was “ a gesture of appreciation”. He added: This was a huge win for all of us, including Andy and myself, for the relationship. That's why I went to him, because I just felt very grateful that he's there.”

Zverev, who is seeking his first Grand Slam title, beat No.12 seed Tommy Paul 7-6 7-6 2-6 6-1 to reach his third semi-final here.