Alistair Johnston knows it won’t be long before his mind inevitably drifts towards what really tempted him to Celtic in the first place.

The right-back is the first to confess his body needs a breather having bounced from a MLS season into a World Cup, then straight from Qatar to the pressure cooker at Parkhead. It’s no wonder he’s feeling a bit knackered.

But the enthusiasm does not fade from his voice when the conversation turns towards the Champions League. Even as he basked in the glow of Celtic’s treble-winning celebration on Saturday, the Canadian can’t help but get excited at the prospect of his debut season at European football’s most exclusive members club.

There’s that, plus the fact Johnston outright states Celtic are targeting another clean sweep next year; the kind of thing you’re allowed to say after a fifth treble in seven seasons. But first, he’ll allow himself a moment to process it all.

“I’m just going to have to reflect on it,” he said. “It’s been a great year for me personally. I want to enjoy my off-season and get my body ready to go as this is going to be the expectation next year.

“It’s going to be can we do a treble again? And can we make that next step in the Champions League? As that’s where this club belongs and what we need. I feel like we need to take those next steps.

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“That was one of the reasons I wanted to come to Scotland because there was that ambition to do something more in Europe. And that’s where my mind’s at now. We need to start the season right on the front foot and take that form into the Champions League.

“I’ve done a full season in MLS and then going to the World Cup and then coming here it’s been a whirlwind. That’s the best way to describe it. It’s been a long 18 months but it’s been really enjoyable.

“My body has definitely started to deteriorate over these past few months but at the same time when you have the opportunity to go for a treble that helps you push through that pain barrier.

“I’m happy with that and I will get a nice week or so before I’m back into international football. But that’s the life. It’s been a great start to life at Celtic.”

That last sentence is perhaps a little modest. Johnston has averaged a trophy for roughly every seven games he played for Celtic thus far, a clearly unsustainable ratio but one which underlines a whirlwind few months for the 24-year-old.

Johnston is another of Ange Postecoglou’s signings who have bought wholesale into the club and its close connection with supporters, and he was again blown away by the atmosphere before, during and after Saturday’s Scottish Cup final success over Inverness Caledonian Thistle. Trips to Hampden have been a regular occurrence for the defender thus far, but he’s not being fooled into taking that for granted.

One look at the likes of Callum McGregor making the extraordinary ‘almost ordinary’ with his fifth personal treble tells Johnston he is among truly special company.

“Yes, I try to do my best to take it in,” he said. “You can see when we score I really just try to soak it all in because it’s not normal, this kind of passion. It’s only a select few football clubs that have that kind of atmosphere, especially when you come to a neutral ground like Hampden and there is still so much passion there.

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“I really try to enjoy it but I will need to take a moment to look back on this season, the World Cup and then winning a treble. When you look at it like that I think it’s the fifth treble in the past seven years. For guys like Cal, it’s something that becomes almost ordinary but if you look at the history of this football club, it’s unbelievable history, it’s only the eighth treble.

“So we have put ourselves in a pretty special group. That hasn’t really sunk in with us all yet but we have put ourselves in the history books. The gaffer said it afterwards. That’s all you can ask for.”

Elsewhere in the dressing room, Joe Hart now stands as only the third player in history to sweep up every major honour in Scotland and England. He joins Kenny Dalglish and Andrei Kanchelskis in that elite bracket, one that caps a true career renaissance for the veteran goalkeeper.

At 35, some may feel time is running short for the former England international, but Johnston insists he still has drive and enthusiasm of a much younger player.

“That’s some feat,” Johnston insisted. “And no better guy to have done it. Just a top professional. I don’t know how old he is but he acts like he’s 24! He’s a constant livewire who could talk to anyone. Sometimes when you come into a changing room where there’s a guy with that resume and presence then often they can put themselves on a bit of a pedestal.

“But he’s not that guy at all. He comes down to everyone’s level. He doesn’t need to do but he does and everyone appreciates that. He makes everyone feel right at home. He’s the most deserving guy to have done that and I’m happy for him. It just goes to show what a career he’s had with 75 caps for England. He’s one of those players who’s often overlooked by a lot of the English media and fans. I’m really happy for Joe, he deserves it.”