Kewell and Arnold were reported to have fallen out when Arnie took charge of the Socceroos in the wake of Guus Hiddink’s departure after the 2006 World Cup campaign.

At the notorious 2007 Asian Cup campaign where Australia disappointed, Arnold controversially claimed: “Some players do not want to be here.”

And in 2008, Kewell was alleged to have let it be known he did not want to be part of Arnie’s Olyroos squad as an overage player in Beijing for the Olympics.

Ten years later though, Kewell admits Arnie has matured as a coach during his time with Central Coast Mariners and Sydney FC.

And he now sees him as the natural replacement for the Socceroos coach whenever Ange Postecoglou moves on.

“Graham Arnold – obviously me and him had some interesting times together,” said Kewell today at the launch of the Russia 2017 Confederations Cup publicity drive in Sydney.

“But the coach he has turned into is phenomenal. The way he has got his teams playing, especially in the A-League, is fantastic.

“He’s a guy that is progressing as a coach.”

Kewell said Arnold was “100 percent” in line to replace Postecoglou when the position next comes up.

“Of course. If you look at him, he’s a home-grown coach – you’re looking at someone who knows the players, someone who’s won titles…” said Kewell.

“He’s doing everything positive. His season this year with Sydney FC is phenomenal. They’re two points away from winning the league…no-one can catch them.

“He’s doing extremely well.”