The limited time he had to effect change and the nightmare draw of Spain, the Netherlands and Chile in Group B, though, had many fearing that Postecoglou’s inexperienced team might be humiliated in Brazil.
That looked like being the case for the first 14 minutes in Cuiaba as Chile ran rings around the cautious Australia defence and charged to a 2-0 lead with goals from Alexis Sanchez and Jorge Valdivia.
Far from folding as they had in Brasilia and Paris last year, though, Australia rolled up the sleeves on their gold shirts and battled their way back into the game.
Tim Cahill, one of the few members of the golden generation to survive Postecoglou’s cull, scored with a trademark header on 35 minutes and the game was very much in the balance until Jean Beausejour grabbed a third for Chile in stoppage time.
Impressive performances from young guns like winger Mathew Leckie, playing just his eighth international, and the solid structure of the side indicated that Postecoglou’s rebuilding project is on the right track.
Most importantly for a country where giving up before the end of a sporting contest however heavy the odds are against you is simply reviled, the Socceroos showed they had rediscovered their fighting spirit.
They are likely to need it too with the Netherlands, who humiliated world champions Spain 5-1 in the other Group B match on Friday, up next in Porto Alegre next week.
Postecoglou will probably need a new right back to face the rampant Dutch attack after a dejected Ivan Franjic limped out of the match against Chile with a knee injury.
It will not be as straightforward a choice as it might have been.
In what appeared to be his last decision before announcing his final 23 for Brazil, Postecoglou decided to ditch 80-cap right back Luke Wilkshire.
Ryan McGowan did a solid job as a substitute for Franjic against the Chileans but is more comfortable in the centre of defence and was given a torrid time by Neymar in the Brasilia thrashing last year.
Still, Australia feel they could, or should, have got a point out of the Chile match and will go on to face the Netherlands and then the Spanish in Curitiba on June 23 with renewed belief.
“We’ll learn from this and we’ll go into the next game very positive,” Cahill told SBS TV.
“The good thing is, we believe in our football, we believe in our structure. Last week they were questioning whether we can create chances. Tonight we created quite a lot.”
(Editing by Justin Palmer)