Postecoglou left Celtic following a trophy-laden two years to join Tottenham at the end of last season.
There was an expectation that the Australian would need some time to implement his ideas at Spurs but he has made a blistering start to life in the Premier League.
Spurs have gone into the current international break sitting at the summit of the Premier League standings after eight games.
While no one is expecting them to win the league, Spurs are now firm contenders to at least finish in the top four this season.
Arnold claimed that the whole of Australia are now backing Tottenham for what Postecoglou has done at the club.
He insisted that even Australians are now coming to terms with how good the Spurs boss is as a coach.
The Australia manager told The Athletic: “Honestly, I think the whole of Australia has become Tottenham fans.
“Ange has been remarkable.
“What he’s doing has really opened the eyes of the country as to how good he is and how good Australian coaches can be.
“The whole of Australia is loving it.
“Ange just laughs and shakes his head.”
Postecoglou’s style of football and his off-the-field demeanour have even won over neutral fans in the Premier League.
