Boris Becker turns his back on protege in favour of rival months after coaching split

has snubbed months after stepping down as the Dane's coach.

The seven-time Major winner linked up with the 21-year-old at the end of last season but later said he couldn't give Rune as much time as he needed.

Becker now believes one of Rune's rivals has better prospects as he named the next player who can join Carlos Alcaraz and Jannik Sinner at the top of the game.

Alcaraz and Sinner have set themselves apart from the rest of the pack. The young stars occupy the top two spots in the ATP rankings and they've split the Grand Slam titles this year.

Before they pulled ahead of their colleagues, they were previously tipped to be part of a 'new Big Three' along with Rune. But the Dane has been left behind while the Spaniard and the world No. 1 forged an exciting new rival.

Becker now wants to see a third man step up to become the Rafael Nadal of the group, suggesting that Sinner is the new Djokovic and Alcaraz is the new Federer.

Despite coaching Rune less than a year ago, the German says Rune has stalled and been overtaken by another rising star.

"We can define Sinner and Alcaraz as the Djokovic and Federer of the future, although we must keep the proper proportions," Becker told .

"Roger and Nole have made history in this sport, as has Rafa Nadal. Alcaraz's style of play, in terms of beauty, is more similar to that of the Swiss, although his idol has always been Rafa.

"From a purely stylistic point of view, the Spaniard can be compared to Federer and the Italian to Djokovic. However, we now have another dilemma on the circuit. We need a 'Nadal' to complete the new Big Three and another player to follow the 'Fab Four'."

Although Rune had once been put in the same bracket as Alcaraz and Sinner, his old coach believes he has been surpassed by Ben Shelton. Becker continued: "The one who for me is closest to reaching the top is Ben Shelton.

"The most prepared, at the beginning, seemed to be Holger Rune, but he has not progressed much this year. However, I also watched the American for a long time at the Laver Cup, in singles and doubles, and I liked his attitude. He smiles, puts on a show and has fun."

Becker could have had the opportunity to help Rune progress. After joining his team last October, he committed to working with the Dane in 2024 but they parted ways after the Australian Open.

"Due to professional and private responsibilities, I can't give Holger what he needs now. I wish him only the very best and I'm always going to be his No 1 fan. I truly appreciated this journey together," the 56-year-old wrote on social media.