The coach of the men in green and gold says his players have what it takes to be far stronger next time they find themselves on the biggest stage in world football
The Socceroos went down 3-0 to Spain in their final match of Group B in Brazil and will return home empty handed but with their pride intact, particularly after encouraging performances against Chile and the Netherlands.
Attention now turns to the Asian Cup on home soil in January and the qualification campaign for the next World Cup, with Postecoglou talking up his team's chances of making an impact in future competitions.
"We've certainly got some positives out of it and stuff we need to work on," he told SBS.
"We wanted to come to this World Cup and try to take it to three absolute world class teams. I think we've done that. What we've found out is we're not at that quality yet.
"In four years' time, if we keep having that sort of intent, I think we'll bridge the gap and hopefully come back and be the team that's more dominant than the opposition."
A goal from Melbourne City-bound David Villa saw Spain, the 2010 winners but already out of contention at this tournament, lead at half-time in Curitiba, before Fernando Torres and Juan Mata finished Australia off in the second half.
It was something of a flat finish for the Socceroos who, with nothing to lose, had been tipped by some to worry Vicente Del Bosque's demoralised team.
"It's disappointing," Postecoglou said.
"We started bright enough but you've got to pay credit to them. They're a quality team. We looked a bit jaded and a bit tired to be honest. They worked us around really well, we gave the ball away a bit too easily and made it really tough for us."