Rafael Nadal has admitted it is hard to see world number one Novak Djokovic losing too many games in 2016.
The Serbian star has been the talk of Melbourne heading into the Australian Open, which gets underway on Monday, but while the likes of Roger Federer and Stan Wawrinka have talked down his form, Nadal has admitted he will be hard to beat.
When asked if Djokovic had ascended from the "big four" and into a league of his own, Nadal said: "I don't know, you call it big four.
"Now maybe 'big one' is your name, not my name. I really don't care much about it.
"The only thing that is true is Novak is playing at a better level than the rest of the players now. That's obvious.
"The way he's playing it's difficult to see him losing matches.
"I can just congratulate him for making that happen."
But Nadal said things can change quickly.
"He's an amazing player, but the second good thing is he never has injuries, so that helps a lot to have full confidence in yourself and to never lose the rhythm," he said.
"It's going to be decisive if he can keep going that way with no injuries.
"I hope to be there fighting closer to him."
To get there, Nadal will have to overcome a tricky first round match against fellow Spaniard and good friend Fernando Verdasco.
The two famously met in the 2009 Australian Open semi-finals in a five-set thriller which Nadal won 6-7 6-4 7-6 6-7 6-4, before moving on to beat Federer in the final.
"It's a very tough first round, it's not a lucky first round for me or for him," Nadal said.
"I t will be a tough match and I need to be ready to play very good tennis if I want to be through.
"That match [in 2009] gave the the chance to win the only Australian Open that I won. It was an unforgettable memory for me."