After winning the first three matches in the second round of Asian Group B the Socceroos are well on track to reach the final stage of qualification for the tournament in Russia.
Postecoglou however has a crucial decision to make before he can entertain any hopes of becoming the first coach to take Australia to two World Cups.
The problem is what to do with his two 'fantasistas' - Massimo Luongo and fit-again Tom Rogic.
The two British-based stars are probably the most gifted players in the team, from a purely technical point of view.
It is a joy to watch them in full flight because they have the poise, balance and finesse to trouble any team.
Yet they are so similar in style and temperament that it is hard to see them play together in a 4-3-3 formation.
They bring plenty of class and creativity to the front third when Australia is on the attack and the fans expect something special to happen whenever they have the ball. That's how good they are.
But what happens when the Socceroos lose the ball?
Would these attack-minded midfielders become a liability rather than an asset, since defending is not their forte?
Would they expose the team's holding midfielder if they fail to track back quickly enough?
In other words, are Rogic and Luongo a luxury Postecoglou can ill-afford?
The away qualifiers against Kyrgyzstan and Tajikistan illustrated very clearly that the Socceroos can be vulnerable to quick counter-attacks.
Thankfully the level of the opposition was not high enough for Australia's weakness to become costly.
One wonders what will happen when the Socceroos inevitably face better teams in the third and final phase of qualifying.
Postecoglou is highly unlikely to tamper with his favoured 4-3-3 that has brought him much joy in recent years.
So a straight 3-5-2 or a 4-4-2 are simply out of the question.
Which leaves the coach with the middle three spots to fill.
It is presumed that Mile Jedinak or Mark Milligan are locked into the holding role, which leaves Postecoglou with two positions to fill.
With Aaron Mooy or Matt McKay showing that they are more than capable of doing the job from a defensive perspective, Postecoglou is left with the key No.10 role to fill.
Which is where Celtic's Rogic and Luongo of Queens Park Rangers come in.
It is not the first time that national team coaches have had to solve the problem of two quality players to fill one role.
Italy's Ferruccio Valcareggi had to pick one from Gianni Rivera and Sandro Mazzola at the 1970 World Cup and ended up giving them 45 minutes each.
Helmut Shoen faced a similar scenario with Wolfgang Overath and Gunther Netzer four years later and plumped for the former.
Cesar Luis Menotti opted for Ricardo Villa in 1978 at the expense of a young Diego Maradona.
The way Postecoglou handles this 'dilemma' will go a long way towards determining whether the Socceroos reach the World Cup finals in Russia.
In a way it's his football version of Russian roulette.
