Celtic's success under Postecoglou attracts Premier League interest
The Australian has now won four trophies in his first two seasons in Glasgow and will expect to complete a domestic treble this season when the Hoops take on Inverness Caledonian Thistle in next month's Scottish Cup final.
The scepticism which greeted Postecoglou's appointment when he was plucked from Yokohama Marinos in Japan has long been forgotten.
Instead Celtic now face a fight just holding onto him as the 57-year-old has been linked to the vacant managerial jobs at Chelsea and Tottenham.
It is Postecoglou's style as much as the substance of results and trophies that has the former Australia national boss receiving admiring glances from Premier League giants across the border.
Celtic have racked up 95 points and 105 goals in winning the league with four games to spare.
Both the club's record points tally of 106 and goals scored of 116 are under threat in the final weeks of the season.
"As much as we get defined by success, which means winning trophies and games of football, I guess the most pleasing thing for me is the number of goals we've scored because I still think that's the best part of football for me," said Postecoglou.
"If there's one record I'll be most proud of, it will be if we can score more goals than have ever been scored before by the football club because I know how much joy that has brought everybody involved, players and supporters."
Postecoglou's mantra of "we never stop" has been embedded into his players and the Celtic fanbase at large ever since the club posted a clip of one of his first training sessions on social media.
A relentless, front-foot approach has been far too much for their rivals in Scotland to cope with.
Since losing three of his first six league games as Postecoglou oversaw a huge turnover in players, Celtic have lost just once in the Scottish Premiership in 66 matches.
Two Rangers managers have left Glasgow in that time and the current occupant at Ibrox, Michael Beale, is already under pressure after failing to win any of his first four meetings against Postecoglou.
But with domestic dominance now the norm, Celtic are no longer satisfied by success in Scotland.
The next frontier is to finally make a meaningful impact in Europe.
Celtic bloodied a few noses when faced with the might of Real Madrid, RB Leipzig and Shakhtar Donetsk in the Champions League this season but lacked the knockout punch and finished bottom of their group.
For the second consecutive season they will go straight into the Champions League group stage thanks to winning the title.
The riches of Europe's elite club competition threaten to only widen the chasm between the newly-crowned champions and the rest of Scottish football.
But Celtic face the same problem when they step out of the small pond of their domestic market to take on the best in Europe.
That is the challenge that now faces Postecoglou and his suitors down south will be watching.