John McEnroe says "you never want to count Novak Djokovic out" despite his failure to win a grand slam in 2024.

Djokovic's last major triumph came at Flushing Meadows last year as he won his third grand slam of 2023, levelling Margaret Court's record of 24 titles.

And it looked like he would overtake that record this year, but he has struggled with injuries and a lack of form, meaning he will end a calendar year without a major title for the first time since 2017.

While he ended his wait for a gold medal at the Paris Olympics last month, he only reached one grand slam final, losing in straight sets to Carlos Alcaraz at Wimbledon.

He then suffered a shock early exit to Alexei Popyrin in the third round in New York, but McEnroe is convinced the Serb has what it takes to prove everybody wrong.

"You never want to count him out," McEnroe told Eurosport.

"This would certainly be the first time where you could say with some seriousness that you start to wonder if he's going to win again.

"How long can this guy keep motivated? Then he won the Olympic gold. I'm amazed that he's kept it [motivation] for this long.

"I'm sure to be surprised either way. If he doesn't win [a major], you would be like wow – he won three of the four last year. And now we're saying he'll never win it again. And then I would sort of be surprised in a way if he did, because of his age.

"That's what he's facing right now. It will be interesting to see if he's able to pull it off. But I do think he'll try to find that motivation to get number 25."