When he sits back to reflect on a long career some day in the future, the decision to sign for Celtic may just move to the front of Joe Hart’s mind.

It’s no exaggeration to say that the goalkeeper had never really recovered from being exiled by Pep Guardiola at Manchester City in 2016, not until he stepped on a plane to Glasgow. Following his departure from the Etihad, Hart bounced around unremarkably from Burnley to Torino then back to England with Tottenham, where he made only 10 appearances, none of them in the Premier League.

Naturally, the reputation of a man once described as ‘a phenomenon’ by Lionel Messi had taken a hit, so much so that Celtic’s decision to sign him to cover what had been a problem position did not garner overwhelming approval. But club and player have proven a perfect match, shrewdly facilitated by Ange Postecoglou.

Now, Hart says the Celtic manager is casting serious doubt on the validity of that one about old dogs and new tricks. His experience at Parkhead has made him ‘feel alive’ in football once more, and he projects a sense of not wanting it to end any time soon.

“A huge impression, he’s top,” Hart said of Postecoglou’s impact on him. “He’s really, really good. He’s very clear on what he wants and I think the biggest buzz for me is that I am playing for someone who is pushing me and I’m learning new things every single day.

“I’m an old dog in this game and the fact I am having to do that and stay on my toes and still want more and trying to improve is a great feeling. And it really makes me feel alive.

“Of course. There’s no point trying to compare him or us to anyone else. This is the team we have got and the manager we have got.

“But it’s great to be a part of and great to be constantly pushed and get results from it. It’s all very well, there’s plenty of managers out there who will push and it doesn’t necessarily work or players don’t adapt, but credit to the players and the staff we have been able to pull in the same direction and get results.”

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Hart was the homegrown face of City’s early 2010s rise to prominence, turbo-charged by cash from Abu-Dhabi that paid for the likes of Sergio Aguero, Yaya Toure, David Silva and countless others. But the former England international has never felt part of a team with such a clear, defined identity as the one Postecoglou has built, where there is a relentless demand not only to win, but to win in a certain way.

“I love being part of that,” said Hart. “I have played in different teams that have been successful and identity in football has kind of always been there. But in terms of having a real way of playing, this is the first time that I’ve been a part of a team with a real way of playing.

“We live and die by it. And I love that opportunity. There has been many managers and coaches out there I’m sure who have said: This is the way I want you to play and, if it doesn’t work, it’s on me, it’s on me. I’ve heard that many times.

“But I genuinely feel comfortable making risky passes, short passes. And if someone does miss a pass, or gets tackled and the ball goes in, I don’t think any of us would even flinch because that’s what we are being asked to do, we believe in what we’re being asked to do and we are enjoying trying to get better at it.”

Watching from a distance, there were few who appeared to enjoy Sunday’s Premiership title celebrations at Tynecastle more than Hart. Despite all his success at City, this league triumph marks the first time he has become a back-to-back champion. These are days he is determined not to let pass him by.

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“They are special moments aren’t they?” he said. “You can’t take these things for granted. It’s an amazing club to play for and to be champions, personally, two years in a row is a great feeling. 

“I’ve never done that before. We had a gap last time we won it down there [England].

“It’s hard to describe. You just have to be in it because I know from experience tomorrow is just another day and we’ll go again.

“It’s not through lack of effort. Every team that I’ve been in has had good intentions, but I think we have improved, which is a really strong thing to build on having been champions. We have improved from there and everyone has got the attitude that they want to improve, so it is good to be around.”

Going again this week is to prepare for a sixth and final meeting with Rangers at Ibrox on Saturday. Celtic will arrive at the home of their rivals crowned champions, although don’t expect a guard of honour, and can finish the season unbeaten in derby matches.

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Hart, however, insists this is not being treated as an added incentive within the squad. He suggested that delivering a result for the Celtic supporters, of which there will be none inside Ibrox, is of greater importance to the payers.

“There is no extra motivation,” he said. “It’s a huge game for the club. We pull together as a group.

“There’s not going to be any fans inside the stadium pulling for us, but we know there is around the world. Jeez, we went to Australia last November and we felt their presence.

“So we know there is going to be support, expectation and the least we can do is show up with an attitude to win and play our style of football.”