Postecoglou’s side are on top of the Scottish Premiership table as the World Cup break continues and they have travelled to Australia to play friendlies.
On Thursday they took on Sydney FC but suffered a 2-1 defeat despite taking the lead through Kyogo Furuhashi’s 23rd minute strike.
Celtic, although playing away from home, received great support during the game, and the Australian tactician admitted the Hoops supporters are brilliant at creating a great atmosphere in the stadium.
Postecoglou further praised Celtic supporters for providing them with incredible support during home and away games.
When asked about Celtic supporters present in the stadium, Posecoglou told Celtic TV: “Yes, they were brilliant as always.
“Whether it is back home or around the world, our supporters are passionate about the football club.
“They always make a great atmosphere.
“Unfortunately we couldn’t reward them tonight but hopefully we will on Sunday.”
Next, Celtic will take on Frank Lampard’s Everton on Sunday before they resume their season after the World Cup break against Aberdeen on 17th December.