Goals from Massimo Luongo and substitute James Troisi gave the Socceroos a 2-1 win after extra-time in front of a huge crowd at Sydney's ANZ Stadium.
It was Australian football's first major honour, just two months after Western Sydney Wanderers' incredible Asian Champions League triumph.
The Socceroos' success was hailed as our crowning glory by anybody associated with the domestic game and was seen as just reward for Postecoglou's tactical and philosophical rejuvenation of the national team after the bleak and unyielding years under Holger Osiek.
But was that magic moment on January 31, 2015 Australian football's greatest achievement?
There are at least three other moments that could be classified as 'the greatest'.
Make up your own mind.
Reaching the World Cup for the first time in 1973
Rale Rasic's brave men defied all the odds and expectations by reaching the 16-team finals in West Germany.
A thunderous shot from midfielder Jimmy Mackay gave the intrepid Socceroos a 1-0 playoff victory over Korea Republic in steamy Hong Kong.
The match was necessary after both teams were level on aggregate after a home-and-away tie.
What made Australia's achievement even more significant was the fact that Rasic's players were essentially amateur and the team was operating on a shoestring with little or no support from government.
Turning the tables on Uruguay in 2005
Guus Hiddink's Socceroos went into the second leg of their World Cup playoff against two-time world champions Uruguay with a one-goal deficit.
A first-half goal from Mark Bresciano levelled the tie at the same end of the ground where Troisi would apply the killer touch in the Asian Cup final a decade later.
The Australians had chances to win the tie outright but they had to settle for penalties.
A capacity crowd at ANZ Stadium and a vast television audience watched nervously as the shootout ebbed and flowed until John Aloisi hit home the winning penalty before delivering the most famous 'strip tease' in the history of Australian sport.
Australian football's 32-year wait for a World Cup qualification was finally over. The whole country rejoiced.
Coming from behind to beat Japan in the 2006 World Cup
Things were not looking good for the Socceroos in their first match against Japan. Thousands of Aussie fans in Kaiserslautern were shocked to see Australia concede a sloppy goal.
The Socceroos were tentative and it showed but they never lacked the belief that they could turn the match around.
With time running out, they were not to be denied and Tim Cahill acquired instant superstar status by coming on as a substitute and changing the game with two goals.
Aloisi put the issue beyond doubt with a third goal that sent a clear message to the world that Australia belonged at the big end of town.
