ONE night last October, as he so often does, Callum McGregor ghosted onto a lovely James Forrest pass to stare into the whites of the goalkeeper’s eyes. But this was no ordinary night. Bayern Munich were in town on Champions League duty.

It was a massive moment in the now 25-year-old’s career. His credentials at the highest level had been widely questioned, and a golden opportunity to dispel many of those doubts – some he held personally – had presented itself. It was now or never.

Somehow, amid the cacophonous din of Celtic Park on a European night, McGregor steeled himself, maintained his composure, and slipped the ball under the advancing Sven Ulreich and into the net.

Alas, Celtic’s joy at pulling level on the night was short-lived, as a Javi Martinez goal just three minute later burst their bubble. But the consequences of that goal for McGregor were much farther reaching and longer lasting.

“The Bayern Munich game and my goal was probably a big moment,” McGregor said. “As a player you want to go out and impress in the big games, and affect big games, and Bayern Munich are one of the top teams in the world.

“So, to score in that game gave me the belief to go out and think, ‘right, you are worthy of playing here, you are worthy of the big tag, you are playing for Celtic.’ I think since then my confidence grew and I started to perform and play in big games and affect big games as well.

“I think it all came from that moment against Bayern. Maybe a year before that people had been criticising me in the big games and saying that maybe I wasn’t ready for the Champions League. But I went and showed that, if you work hard, you can play there and you are worthy of that stage.”

And McGregor now feels that he is worthy of being one of Celtic’s main men after casting off the self-doubt that hindered the early part of his career.

“I feel as if I am established in the squad and the team,” he said. “If you are doing everything in training and doing well in the games, then you know that you are in with a good shout.

“It is good confidence-wise as well that you know you are going to be in the manager’s plans. But you’ve just got to keep working hard and keep proving that you are worthy of your place.

“Probably my confidence is better. The manager has come in and tactically we are miles ahead of where we were. We are fitter as well. You can see that 90 per cent of the players have kicked on and gone to another level. It is the exact same for me: I’ve gone from way down there to way up here in terms of every aspect of my game.

“There is that confidence side of it too, where I now know that I can walk onto a pitch and affect big games.” The notion of the influence of Brendan Rodgers on the improving form of his players is nothing new, but there is a reason for that. And McGregor is a fully paid-up disciple of the mantra of constant improvement preached by his manager.

“There is the tactical development among all the players so that, when we play our system, we all know that this is what we do, this is how we press,” he said. “It means that, when we do go and press as a team, then everybody is in the right area of the pitch.

“The manager always likes us to express ourselves, but within a structure whereby everybody knows exactly what is happening. When we press, everyone should know where they should be, and when we win the ball, then you can go and show your ability and your confidence on the ball.

“I think this has probably been the biggest change in the team: the tactical ideas that we have.”

Another significant development in the coming of age of McGregor has been a curtailment of the off-field discretions that blotted his copybook in his early career. The attacker now enjoys the quiet life away from the game, so much so that he refuses to indulge in the favourite past-time of his peers by staying away from social media.

“I’m pretty much a private guy,” he said. “When I’m doing my football I’m working, and that’s it. When I’m away from it I have a small circle of people that I really trust, and I think that’s the way it should stay.

“I don’t think you should get ahead of your station and start posting things on social media, it’s just not my style. I don’t do it and I think it has worked for me so far, so why change it?

“My life is pretty much public 95 per cent of the time so when you have time off you want to enjoy it with people that you are close to.

“When you go home, and you are around the people that you want to be around, it’s about you and them enjoying your time together.

“As much as football is my job, and it’s amazing, and it’s what I’ve always wanted to do, and I’m living the dream playing with Celtic, and it’s an incredible achievement… I still don’t feel the need to be posting stuff on social media about what I’m doing, where I am, or ‘look, this is my dinner!’

“I was on Twitter for three or four months when I was at Notts County on loan, and that was it. I came off it straight away and I’ve never had any inkling to go back on it.”