Ange Postecoglou changed the landscape of Australian football and now the trailblazer is tasked with leading an embattled Celtic back to the Scottish summit, having been dethroned by bitter rivals Rangers.

Postecoglou – cut from the same cloth as Pep Guardiola and Maurizio Sarri – was appointed by Celtic last month amid some backlash in Scotland, but Bhoys fans are slowly starting to get an idea of why the former Australia manager is so highly rated.

With an emphasis on a high-octane style of attacking football and unrelenting belief in his philosophy, Postecoglou is the most decorated coach in Australian football history.

From South Melbourne to Australia and Japan, Postecoglou has won it all – a pair of National Soccer League championships, back-to-back A-League titles, a record 36-match unbeaten streak at Brisbane Roar, plus a ground-breaking 2015 Asian Cup triumph with the Socceroos and a J1 League crown with Yokohama F.Marinos - while silencing his doubters.

With fellow Australian Arthur Papas by his side in Yokohama, Postecoglou ended F.Marinos' 15-year wait for league glory in 2019.

As Postecoglou embarks on the biggest job an Australian coach has held in football, former assistant Papas – now in charge of A-League side Newcastle Jets – told Stats Perform: "It's a great achievement to be given a position of such stature.

"I'm ecstatic for Ange because the path to success is never a straight line. That is for everyone. The main thing is he's been consistent. Consistent in who he is as a person, how he approaches his work and what he believes in - and he believes in himself a lot.

"He is incredibly humble and hardworking, and full of self-belief. But he knows it's a big job, a difficult job. Celtic are another team who have fallen away in recent times and the pressure is immense, but I do think that's when he is at his best. He thrives under those conditions. It's a challenge after being so successful in Japan."

Postecoglou left F.Marinos with the highest winning percentage (49.2 – 58 victories in 118 games) in the history of the club. Since joining the Yokohama outfit, only two managers have a better winning percentage than Postecoglou from a minimum of 10 games: Toru Oniki (65) and Go Oiwa (50).

Despite the language barrier, F.Marinos bought into the Postecoglou way. Since 2018, the team ranked first for passing accuracy (86.5 per cent) and possession (63.2 per cent), while they were second for goals per game (1.9), expected goals per game (1.8), shots per game (15.2), shots on target per game (5.3), shot conversion rate (12.6), shooting accuracy (47.2), chances created per game (11.4), passes per game (619.4), passing accuracy in opposition half (82.4), big chance total per game (2.4), big chances created per game (1.8) and big chances scored per game (1.1).

Papas, who spent two seasons with Postecoglou at F.Marinos, added: "It's been well-documented the success in Japan but not really understood how difficult it is. People have asked me, for example, how will I deal with the pressure of being an A-League coach? I feel like saying, being in a country where not one player or staff speaks English and still getting a football message across and seeing it come to life so quickly, has more difficulty than maybe coming back here.

"Every job will have its challenge in the end. The main thing is [Celtic] have got themselves a world-class manager. A manager with a very clear philosophy and someone given the time, like every manager needs. Some use that time extremely well and you see progression, and others unfortunately – because the path isn't so clear, doesn't go that way. But given the time, he will be successful there for sure. He will be successful in his own unique way.

"Then, there will be another step after that because that's just Ange. He doesn't settle for that place and get comfortable. When he has had a bit of success, he wants more. That's why he is special at what he does."

Postecoglou, like Manchester City's Guardiola and former Chelsea and Juventus boss Sarri, pushes the boundaries. Firmly set in his belief of how football should be played, Postecoglou's approach never waivers and success follows the 55-year-old in his pursuit of excellence.

Asked about some of the initial negativity after Postecoglou's arrival at Celtic, Papas said: "Australian coaches, unfortunately, don't get start-up respect regardless, so there's always going to be someone that doubts you. What is important, is what you believe in about yourself.

"The thing is, he is so supremely confident in himself that it won't phase him. He knows it's just part of the challenge of where we are from and where we're going. He is a firm believer of it, we as Australian coaches probably get underestimated because of our passport not because of our competency. Having experiences across Asia, you see things and you're like wow.

"The passport unfortunately doesn't carry a lot of weight and definitely carries a lot of criticism at times, but he believes in himself.

"He will go there, it will take some time to engrain his ideas but there's no doubt they have a world-class manager that will turn that place upside down and get them on the right path."

During F.Marinos' triumphant season in 2019, Postecoglou's men covered the greatest distance in the J1 League (116.48km), ahead of Oita Trinita (114.79km). They also tallied the most total sprints with 191, more than FC Tokyo (174).

"Ange is the type that scours through every bit of information. If you're a staff member there, you need to be on top of everything because you'll get questioned at times about 'what was the data on this?', 'what were the statistics on this player?' He is obsessed with his work," Papas added.

"It doesn't matter how time progresses; he is just as obsessed as he's ever been in terms of details. There's a lot of work to get that engine going in the background to run that program in a way that he feels befits a world-class program."

Postecoglou oversaw a rebuild at the Roar and after asking to be judged a year from the time he replaced ex-Socceroos boss Frank Farina, his project culminated in the development of arguably the greatest footballing side the country had ever seen.

Playing an entertaining and possession-based brand of football, the Roar won the championship in 2010-11 and successfully defended their trophy the following season amid a 36-game unbeaten streak – an all-time Australian football code record for the longest undefeated run, surpassing rugby league outfit Eastern Suburbs' record set 74 years prior.

Postecoglou also coached Melbourne Victory before his Australia appointment in 2013. In the A-League, his teams scored 1.7 goals per game; only one head coach (minimum 30 games) has a higher average in the competition's history (Graham Arnold - 1.8).

The Greece-born boss left Australia's domestic competition with a 51 per cent win percentage as head coach – the joint-fifth best of any manager in the competition's history.

Named Australia boss in 2013, Postecoglou led Australia at the 2014 World Cup, conquered the Asian Cup the following year and also secured their position at Russia 2018 before stepping down. The Socceroos scored 86 goals in A-Internationals under Postecoglou – the second most they have scored under any manager since the beginning of 1965 (Frank Farina - 197).

Australia won 22 games during his tenure; only two managers have won more since the beginning of 1965 (Frank Farina - 34 and Holger Osieck - 23).

"I don't believe there is a certain timeline and it clicks," Papas said. "The process starts from day one and it's more about what is around you to implement that. Certain positions, you can go in and have the ability to make certain changes early on, which might fast track that progression. The only thing is that it's something that always grows and gets better. Because it's such a clear way of working and style of play that you're constantly working on everyday getting better at doing that.

"It's not, this week we're going to change it and sit back, these messages are so consistent that it just becomes something you get stronger at over time but that's why it takes a bit of time also. It's not a situational philosophy, it's a very clearly-defined progressive philosophy that has clarity and certain principles/frameworks that get reinforced on a daily basis."