The 39-year-old remains humble in the light of what he calls his “greatest honour”, an achievement that so obviously means so much to him as an athlete and a person.

“I really believe that once you are a champion, you are always a champion,” says St-Pierre, on a call from his home in Montreal. “To be a Hall of Famer is a great honour. You’re in a different zone now, you’re among the elite. And for me to be among the elite in the sport of mixed martial arts, it’s the greatest honour.”

In an age when sports fans seem trapped in a 24-hour cycle of online cynicism about the people we watch in action, St-Pierre has always appeared as though drawn here from another era, back from when sports fans truly believed the words they heard, and they held their heroes in higher esteem.

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Put part of that down to the origin story St-Pierre carries around with him, that of a child on the streets of small-town Quebec being bullied, and living every day in fear of being assaulted simply because of the way he looked. The child who turned to martial arts to protect himself, and who turned those horrors into his life’s driving force.

“Being bullied helped me deal with the situations I faced later, in my career,” says St-Pierre. “Because when I was young, and five guys would wait for me at the bus stop and they were older than me, and I would get my ass kicked, I was scared. But fighting a guy I know I am going to beat because I am better than him, that doesn’t scare me.

“In my sport there is a lot of mental warfare. There is a lot of trash talking. There is a lot of intimidation. A lot of my opponents tried to intimidate me. It didn’t work. I’ve always been scared, of course, but I am scared of not being good enough, of not performing, or not being as good as I want to be. That’s what I am scared of. I am scared of myself in a way.”

Part of the St-Pierre mystique, also, is how he always appeared to be one man inside the Octagon, and a totally different character once he stepped away from the cage. A thought to emphasise the fact when the call comes in from Montreal – at the exact second it has been scheduled for – St-Pierre says he's been gardening and reading and doing the household chores.

“When you fight it is a little bit like you have to be a super hero, like Clarke Kent turning into Superman. Batman and Bruce Wayne,” he says. “You’re the same guy but you are two different characters. And that’s what I become, a little bit. When I fight, I fight. When I go home I go home. And I don’t like to bring my work home.

“When I’m home or with my friends and family, I’m a nice guy. I’m a different person. My job was to hurt people. I never wanted to hurt someone but I had to do that to win. To win you have to hurt people. I needed to become someone else, unlike the person I am in real life. But when I train I still unleash the beast.”

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St-Pierre walked away from MMA while still at the very peak of his career, coming off a third-round win over Michael Bisping to add the UFC middleweight title to a collection that already had included the welterweight crown, and nine title defences of it.

Health issues involving ulcerative colitis had meant he was struggling physically but St-Pierre acknowledges there were struggles with the mental side of the fight game that always lurked in the shadows as he fought his way to a 26-2 record, overall.

“I was always very scared,” says St-Pierre. “I couldn’t sleep well the night, a few nights, before the fight. It’s my fault a little bit because you control your own mind and I always performed better when I put pressure on myself, when I felt like I was on the edge. So I forced myself to feel that way, scared I wouldn’t win, or I would be humiliated.

“But the stress took a lot out of me and that’s one of the reasons why I retired. I retired not because I can’t fight any more. I could fight again if I wanted to and I believe I could probably be one of the best, maybe the best. But I stopped because of the stress.”

Inside the Octagon, St-Pierre faced and beat the best of his generation, and he did it his own way, the likes of fellow Hall of Famers in Bisping and Matt Hughes and Matt Serra and B.J Penn unable to cope – in the end – with the combination of skills crafted through karate and BJJ and Muay Thai.

Rumours continue to swirl that he might one day return, and St-Pierre himself has never entirely ruled it out of the equation. There are regrets, he says, as those stresses meant he couldn’t ever fully enjoy his achievements inside the cage.

“It was an unbearable feeling for me, so I never enjoyed it, the moment of competing and fighting,” he says. “That’s something that, a little bit, I regret. I should have enjoyed it more. But in my sport a lot of people retire too late. Not only in MMA but in boxing. The fighter is always the last person to know when to retire. So one of the things I didn’t want to do is retire too late.

“Yeah you never say never but for me right now I am very satisfied with what I have done and I believe in an extreme sport like MMA that when you are satisfied then it’s the end.”