For the opening half hour, Australia was completely at sea against the Germans and by Postecoglou's own admission, the Socceroos could have been three or four down at halftime.
Australia didn't give up, though, and scored a second goal to get back into the game.
Australia coach Ange Postecoglou was puzzled to learn the reasons behind his side's lack of "composure" in a sluggish start at the Confederations Cup against Germany on Monday.
"Communication-wise we weren't getting organised in defence and we didn't get that sorted until well into the game".
"They were way too good".
"I'm disappointed with the result but not the performance of my players".
The Canberran - clearly Australia's best player - kept his composure to score at the second attempt from long range, after his first was blocked, to shock the 28,605 at the Olympic Stadium.
The Socceroos will next face Cameroon before a final group clash against Chile who themselves beat Cameroon 2-0 in the first game of the group.
Cameroon are unlikely to offer the same threat as the Germans, even if the world champions have come to Russian Federation without a host of leading players.
"There's no question we're a team full of character and courage", he said. "We made it too easy for them".
"They probed for weaknesses, they capitalized on the opportunities they had".
"People forget this was an award for something we achieved", Postecoglou snapped back. Russian Federation is their third appearance at the Tournament of Champions - they went out at the group stage in Mexico in 1999, although managed to claim third place as hosts in 2005, thanks to a 4-3 win over Mexico in their playoff.
However, his opposite number Joachim Loew said Australia have developed since Postecoglou took charge in 2013.
Germany is one of the strongest teams in world football, and are also looked upon as favourites to win the ongoing Confederations Cup in Russian Federation. Considering that this team boasts the likes of Julian Draxler, Emre Can, Marc-Andre Ter Stegen and many others, though, it's not hard to see why they're in that position.
Australia's encouraging showing after half-time echoed their efforts in the 2014 World Cup - competing with a leading nation only to end up on the losing side.
"Who'd expect everything to be flawless after only 10 days together?"
"In the second half we said 'let's stick to our principles". We worked a little bit smarter defensively and we were good with the ball and scored a goal.
"The key for us is to believe in the way we play", said Australia's veteran midfielder Tim Cahill, 37, in yesterday's press conference.