World No 1 Novak Djokovic said the future of men's tennis was in good hands Tuesday, praising the new generation for showing "courage and boldness" in their pursuit of Grand Slam glory.

Djokovic, Rafael Nadal and Roger Federer have dominated the sport over the past 15 years, holding a vice-like grip on the major titles, with 57 between them.

But their reign is being threatened, with Dominic Thiem winning the US Open last year and the likes of Alexander Zverev and Stefanos Tsitsipas knocking on the door.

Ahead of next week's Australian Open, 17-time Grand Slam winner Djokovic said it was good to see the next generation performing well.

"It's great for the sport that we have new Grand Slam champions," he said after leading Serbia to a 2-1 win over Canada in the ATP Cup in Melbourne.

"We have new successful young players that are showing the courage and boldness, coming into the biggest stadiums in sport, willing to take on the biggest challenge in facing especially the three of us, fighting for the biggest title.

"There are a few of them that are very close. They have huge potential. Obviously there's still a lot of time ahead of them."

Djokovic pointed to Tsitsipas, Zverev, Denis Shapovalov and Matteo Berrettini as capable of breaking through. "You have a lot of players. I think the future of tennis is in good hands, without a doubt," he said.

Xinhua-Agencies