Dominic Thiem is the best player after Novak Djokovic, Rafael Nadal and Roger Federer, according to Boris Becker.
The 'Big Three' have dominated the game for over a decade with only really Andy Murray proving himself able to regularly compete with them.
Becker, though, thinks there is a solid group now forming behind them, and says Thiem is most primed to pounce.
"The best player behind the Old Gen is Dominic Thiem," Becker told Sky Sports.
"He has the experience in Grand Slam finals. He played a very good match against Djokovic in the Australian Open final last January."
While Becker believes Thiem is the best of the rest, he believes there are more players than just the Australian who can begin to vie for the biggest titles.
"I enjoy watching Stefanos Tsitsipas, and Alexander Zverev showed that he is very competitive at Grand Slam level at the Australian Open."
Whoever manages to break the monopoly of the big three, Becker says he hopes they are beaten at their best rather than simply allowed to fade away unchallenged.
"I would like to see Novak Djokovic, Roger Federer and Rafael Nadal still at their best, and being beaten.
"Maybe 2021 will see the breakthrough of the young guns because they will be a year more experienced, and the older players are another year older.
"I don't want the young generation to take over when the top three aren't playing anymore or are actually too old."