And judging by Lleyton Hewitt's sensational return of serve to Bernard Tomic and the incredible Australian Open runs of wildcards Alex Bolt and Alexei Popyrin, the former world No.1 and four-times Melbourne Park champion may well be right.

Bolt and Popyrin's spectacular forays to the last 32 have blown Tomic's assertion that the unheralded pair were gifted entries to the season's first grand slam only because they were under Hewitt's wing out of the water.

Tomic also said he and fellow former Cup spearheads Nick Kyrgios and Thanasi Kokkinakis no longer wanted to play for Australia on Hewitt's watch.

Kokkinakis and Kyrgios have done little to douse the flames since farewelling the Open in the first round, respectively refusing to endorse Hewitt as Australian captain and and condemning the skipper for his heavy focus on Alex de Minaur.

Hewitt is unconcerned, though, after Bolt and Popyrin not only vindicated his wildcard selections, but de Minaur, John Millman, Matt Ebden and Jordan Thompson assumed Australia's top four rankings positions after their progression to the second round or beyond.

Agassi, one of tennis's great rebels before ending his career as a statesman and icon, admitted he regretted his clashes with some of his Davis Cup captains.

"I don't know about the politics and whatnot that go on and as Davis Cup captain what his responsibilities are," the American told AAP during his trip to Melbourne as a global ambassador for Lavazza.

"I can only imagine. I only saw it as a player.

"I probably took a lot for granted and I said regretful things in my own life about captains when things didn't go the way I wanted them to go.

"Lleyton, he's been nothing but a competitor for this sport. I've always respected him.

"He's a fighter and I'm sure he's going to fight on behalf of making his team as good as possible.

"I'm sure he's a pretty smart dude as well when it comes to that.

"It's not easy if you don't get the support from certain players, but Lleyton has won more battles than that."

Australian Associated Press