Boris Becker remains impressed by the longevity of Novak Djokovic – but the German icon knows the Serb cannot continue his winning ways indefinitely.

Becker, coach of Top 10 Dane Holger Rune, has issued a stark – if realistic – warning on the staying power of the world No. 1, still atop the table at age 36.

The former coach of Djokovic during the 2014-2016 period when the Serb won six of his Grand Slam titles said: “You’re not really meant to play tennis like that at the age of 36.

”When does the guy get tired, or when does he run out of motivation?”

While Djokovic lifted three of this season’s four Grand Slam titles, Becker predicts the hot streak cannot last in 2024, with young guns Carlos Alcaraz, Jannik Sinner and perhaps even No. 8 Rune nipping at his heels.

The six-time Grand Slam winner says the eager youngsters are likely to “throw a spanner in the works.”

He added: “Novak is the dominator of the tennis scene. (His runner-up finish to Alcaraz in the Wimbledon final) was the best match of the year. 

“He (Djokovic) will be 37 years old next May, whereas Alcaraz and co. will be better and more experienced. 

“I think the best thing that can happen for the tennis scene as a whole is for Djokovic to remain strong and for the younger generation to come closer.

“I still expect Djokovic to win a Grand Slam or two. But I also believe that Alcaraz and co. will more often throw a spanner in the works.

“I hope that this rivalry between the most successful player of all time and the rest of the tennis world continues for a long time, because we tennis fans and amateur players benefit from it.”