Rafael Nadal's powers may appear to be on the wane but the 14-time major winner believes the next star of the men's game is already right under our noses.
"Nick Kyrgios is already at the top," Nadal told fans at a Q & A session during a Tommy Hilfiger press conference in Madrid. "[He is] a player who has an unbelievable potential. He has focus on himself, and can become world No. 1 and win a Grand Slam."
The Australian's season ended in October after he initially copped an eight-week ban from the ATP Tour for 'tanking' during a second-round defeat in Shanghai.
Kyrgios' suspension was reduced to three weeks though, the ATP said, after he agreed to see a sports psychologist. The 21-year-old has been featuring for the Singapore Slammers in the International Tennis Premier League over the off-season.
"[Andy] Murray had an amazing final part of the season but I suppose that players who didn't win a Slam so far, it means the younger players, want to do it," Nadal added. "It's an era of transition where two good generations combine together.
"Mine won a lot, four players of almost the same age [Nadal, Roger Federer, Murray and Novak Djokovic] did so many great things. Now it comes a high level new generation that every year will be even more competitive and ready to fight for important things."
"You will need to see how Kokkinakis will evolve, he suffered and injury and we don't know how he will comeback, but he has the potential to be at the top," he said.
"To me the one that has more chances is Zverev, a complete player in every aspect of the game. I think he will be one of the strongest players."
Like Kyrgios, Nadal's season was ended prematurely in October, when he opted to rehab a nagging wrist injury which saw him withdraw from the French Open and miss Wimbledon.
"I'm practising much, I am in the middle of the pre-season and at the moment everything is going well," added the Spaniard, who will feature in an Abu Dhabi exhibition match on Dec. 29. "I am willing to work and so far I manage to do it."