Appointed by the Hoops last June after a shocking 2020-21 season in which they not only failed to win any silverware but also finished 25 points behind arch rivals and champions Rangers, Postecoglou is the toast of one the world’s most famous football clubs.

Having led Celtic to Scottish League Cup success in June, the former Socceroos coach has now lifted the Hoops to the top of the Scottish Premiership for the first time this season following a crushing 3-0 win over Rangers in the Old Firm derby on Thursday (AEDT).

“I have been pretty lucky – I have had some special experiences in my football career and tonight was right up there,” Postecoglou said after the win, which was highlighted by a superb brace from Japanese midfielder Reo Hatate in front of 60,000 fans at Celtic Park.

However, Postecoglou has made his own luck in a coaching career that, while successful, has also had some unwanted bumps.

He guided South Melbourne to NSL glory in the 1990s before being appointed coach of the Young Socceroos.

But Australia’s failure to qualify for the 2007 FIFA Under 20 World Cup cost him that job.

Postecoglou then had stints at third-tier Greek club Panachaiki and in the then Victorian Premier League with the Whittlesea Zebras.

It wasn’t until he was given an opportunity in the A-League with Brisbane Roar, where he replaced former Socceroos coach Frank Farina in October 2009, that his talents were truly recognised.

Within two years, his “Roar revolution” had turned Brisbane into the best club ever seen in Australian football.

Championship success in 2011 and 2012 led to Postecoglou being appointed Melbourne Victory coach.

From there he took charge of the Socceroos, who won the 2015 Asian Cup under his tenure.

After securing Australia qualification for the 2018 World Cup, he stood down as Socceroos coach and returned to club football with Japanese outfit Yokohama F. Marinos, whom he guided the J.League title in 2019.

Despite Postecoglou’s success, Celtic’s decision to appoint him last year was widely criticised because of his lack of profile in European football.

However, the 56-year-old mentor is having the last laugh.

“I’ve said it from day one – my biggest mission was to get everyone to believe in me,” Postecoglou told SEN after Thursday’s win.

“Whatever ideas I had, whatever way I wanted it to work or do things would be meaningless unless people actually believed in me.

“They’ve been fantastic … even though they probably had to Google me to find out who I am.”

Celtic great Stiliyan Petrov told Sky Sports: “There were a lot of questions raised when (Postecoglou) was appointed but they’ve got a manager who knows what he wants.

“He comes in and says, ‘That’s the way I’m going to play, let me bring my own players, let me bring my own stars’, players who fit into that system.”

However, despite Postecoglou’s joy with Celtic’s “progression”, he also told SEN of his concern that the Socceroos’ development had “stalled”.

A 2-2 draw with Oman on Wednesday morning was a huge blow to Australia’s hopes of qualifying for a fifth successive World Cup.

“The rest of Asia is improving and we’ve kind of stalled in our development,” Postecoglou said.

“The four years I had in charge were fantastic for me. We won an Asian Cup, we qualified for a World Cup, and I think we need to maintain those kinds of standards.

“We should be disappointed if we don’t go to a World Cup.

“Our expectation should be to qualify for World Cups all the time.”