They say the bigger they are, the harder they fall.
And that certainly rings true for Celtic, who have fallen pretty damn hard after nine years on top of the world.
We're less than 12 months into the Hoops' attempt at a 'banter' era, but they have already given their rivals across the city a run for their money. Even the most ardent Celtic defender would admit they have been a shambles since 2020/21 kicked off, with their persistence with Neil Lennon and indecisiveness over Eddie Howe setting them back years.
They've known for months that their long-serving captain would leave on a free transfer, but are yet to replace him, and we've already heard their new manager - in the job for a couple of weeks - criticise the board for their hesitance in the transfer market.
We're in mid-July, and they barely have an 18-man squad of senior players signed up.
Amidst all this chaos, and much to the wincing concern of their expectant fanbase, they have to negotiate a Champions League qualifying tie with FC Midtjylland, who travel to Glasgow for the first leg on Tuesday night.
You'd be forgiven for thinking it would be a minor miracle if Celtic were to get through this tie unscathed. The Danes present a tough test at the best of times, but this is not a Celtic team in any shape for a European game.
Their 'A' squad for the Midtjylland tie makes for some pretty telling reading. They couldn't fulfil the 25-player quota for the tie, and those who did make the cut include; a 17-year-old centre-back; a striker who didn't play in pre-season; a left-back banished to Basaksehir after breaking quarantine rules a year ago; and Anthony Ralston, their only right-back, who made one (just one) appearance in all competitions last season.
Considering it's their first game under a new manager - who typically takes around six months to get his teams firing in the best of circumstances - it will be mightily impressive if they can take anything.
Postecoglou is a top coach, however, and he'll know that if he can somehow get his paper-thin, under-prepared squad off to a flying start, it could just set the tone for the season ahead.
This is the weakest his Celtic team is ever going to be - new signings Liel Abada and Kyogo Furuhashi will add quality, and they are just expected to be the tip of the iceberg of new arrivals - so if they can somehow negotiate their way into the third qualifying round under these circumstances, what does that say about what is to come?
The test facing Postecoglou on Tuesday, and a week later in Denmark, is one of the toughest of his managerial career. The odds are stacked against his team, and they will need every bit of his experience, and that boasted by Christopher Jullien, Callum McGregor and James Forrest, if they are to get through it.
For Postecoglou, however, it's a chance to lay down the gauntlet in his first competitive game in charge, and warn Rangers they have a real fight on their hands to keep hold of