Postecoglu, unveiled as Celtic manager on 10 June, will preside over his first match in charge of the Scottish giant on 8 July in a trial game against Australian international Massimo Luongo's Sheffield Wednesday.
Barely two weeks later, Postecoglou will take on another Socceroos star when Celtic meets Awer Mabil's FC Midtjylland in the first round of UEFA Champions League qualifying.
But nestled among the cluster of early tests for the manager tasked with restoring the club to the top of Scottish Football, one match stands out: the round three Old Firm derby against Steven Gerrard's defending champion Rangers, confirmed for a 9pm kick-off on Sunday, 29 August.
Rangers stormed to undefeated SPFL title in 20-21, with 25 points separating Gerrrard's mercurial team and second-placed Celtic.
They amassed 32 wins from 38 games, scoring 92 goals and conceding only 13 in a record-breaking campaign.
Postecoglou, whose resume includes and A-League championship, J.League championship and an Asian Cup title with the Socceroos, will have his work cut out against Gerrard's swashbuckling side.