Kyrgios, though, admits he's unsure if he'll ever be able to deliver day in, day out like he finally has this summer.

Mark Philippoussis, another of Australia's great unfulfilled talents, has urged Kyrgios to make tennis his priority in order to deliver on his extraordinary potential, while Nadal believes it's inevitable the 24-year-old will if he keeps producing the form he showed at the 2020 Open.

"I mean, I appreciate it. But I already know that. I've known that for the last four years," Kyrgios said in the shattering aftermath to his 6-3 3-6 7-6 (8-6) 7-6 (7-4) fourth-round loss to Nadal on Monday night.

"But the trouble for me is being able to actually just produce the same attitude over and over again.

"Hopefully I can keep doing it. I'm just taking it day by day, trying to be positive, just bring positive vibes."

After starting the summer ranked 30th, Kyrgios is projected to return to the world's top 20 for the first time since August, 2018.

But in a measure of the inconsistency he's talking about, the enigmatic talent hasn't reached a grand slam quarter-final since he was a teenager at the 2015 Australian Open.

"I think I'm playing better tennis than I was (then)," Kyrgios said.

"You look at my draw back then to the opponents I played this time around, probably a lot tougher this time around.

"I feel like I'm playing good tennis. I was a couple points away from winning (against Nadal).

"But that's how it goes sometimes."

For so long the sport's most polarising figure, Kyrgios has won over fans with his new-found calm and focus while leading the bushfire recovery efforts in tennis.

So far Kyrgios has raised more than $60,000 for bushfire victims with his ace tally this summer and the $10,000 John McEnroe chipped in for the 10 sets the Australian won at the Open.

Still, Kyrgios is offering no guarantees about what's to come - other than his scheduled tournament appearances next month in New York, Delray Beach and a title defence in Acapulco.

"I feel like I've made progress as a human," Kyrgios said.

"A tennis player, I don't really care about as much."

Australian Associated Press