Not only was the J-League winner in a new job, a new environment and a new country, he also had to answer the questions being asked of him – who he was and could he turn Celtic around after the first barren season in the east end of Glasgow for more than a decade.
And how soon could he do it?
Postecoglou used the power of persuasion through his attacking football philosophy. It might have created a ‘rocky start’ with Champions League exit and early defeats to Hearts, Livingston and Rangers, but seven months of Celtic are top of the cinch Premiership with one trophy already in the Parkhead trophy cabinet.
“There are always plenty of skeptics every time you get involved and that’s only natural,” he admitted. “That’s the nature of football. There are always question marks when someone gets appointed.
“With me going over, there was a lot of the unknown in terms of who I was and what I was about.
“That doesn’t really affect me. My approach is always the same – trying to get people to believe in me.
“It doesn’t matter how much knowledge I have, and what I believe, if people don’t believe in me as a person then none of it will work.
“Wherever I’ve been, here or Japan or back in Australia, it’s about trying to get people to believe in me.
“It’s about trying to get people to believe in what my values are and the kind of vision I have for the team we are going to be.
The Celtic fans know all about him now, and now they are extolling his work. It’s that newly bridged confidence and understanding that is key to turning around the fortunes, he says, and from the players and staff buying into his methods too.
“I kind of knew what I was heading into. When you’ve come off a season when you’ve won nothing at a club like this … when it happens at a club like Manchester United there needs to be a massive reaction.
“I knew the magnitude of what I needed to do. It’s been pretty good so far and I’ve had tremendous support from the fans and good support from within the football club to take it in the direction I want to.
“But I knew there was always a ticking clock against me to get it right as soon as we possibly could.”
Pressing football was his method of persuasion and once the domestic defeats dried up in September after what he himself termed ‘a rocky start’ the belief has been returned from the players and the fans.
He added: “To come in it’s all about winning games and trophies. I don’t think that’s unique. There wouldn’t be a manager out there who doesn’t want to do that.
“That’s not going to get people’s attention. You need to sell more than that and that’s what I have always tried to do.
“We play a certain way and have certain values. If I can get people to believe in me, those things flow a bit quicker.”
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