Even during the warm-up at Hampden today, the noise from both sides will reverberate around the ground.
With a now-rare 50/50 split of Old Firm fans for the Scottish Cup semi-final, the atmosphere will be bubbling under long before kick-off.
But while the decibels rise outside, deep in the bowels of the stadium’s main stand Ange Postecoglou will sit alone.
Minutes before one of the biggest games of Celtic’s season, their manager will find a quiet spot to READ a book or the match programme.
For the Hoops boss, that period of calm and focus is the perfect preparation for the bedlam that is sure to follow.
Postecoglou has very little interaction with his players before matches.
His work has been done at Lennoxtown in the previous days and weeks.
But as he proved prior to the League Cup Final in December against Hibs, his carefully-chosen words before his team head out can be inspiring.
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Celtic released a recording of Postecoglou’s dressing-room pep talk that was concise but motivational.
He’s hoping to have the same effect on his players today before they face Rangers.
But not until after he has found a spot in Hampden somewhere to clear his head ahead of the mayhem unfolding.
Postecoglou said: “I’ll find a quiet corner and read something to pass the time.
“It’s just to make sure I’m prepared. I gather my thoughts for what’s coming up.
“Once the game starts, my role is to be as observant as possible.
“I have to make sure that if there’s anything out there I can help the players with, I’m sharp in my mind to deal with it.
“So that time before the game is used as preparation for that.
“It’s what I’ve done since the start of my managerial career and it’s my own way of preparing for games.
“Was the League Cup Final speech planned or off the cuff? A bit of both. Whenever I speak to my players, it’s important that whatever information I give is relevant at the moment.
“I have to understand the mood and know what the players may or may not require.
“I don’t speak to the players a lot but when I do I try to make sure they get my message.
“Because whether it’s in the final moments before the game or the lead up to it, my role is to try to provide some guidance to them – whether that’s in a football sense or for the actual occasion itself.
“It’s a little bit of preparation on my part but also, from my experience, what I feel the room needs.”
It’s little wonder that Postecoglou has an air of calm confidence about him now as a Celtic gaffer.
He’s already got one trophy in the bag.
And after battling through a period of transition – and some poor results – they’ve regained the lead in the Premiership title race.
The bookies already have Celtic as champions and, if they beat Rangers in the Scottish Cup today, a domestic Treble becomes a distinct possibility.
His players have fed off his belief in them and vice versa.
In that League Cup Final against Hibs they were behind and won. It was the same at Ibrox in the recent Old Firm showdown.
When they’ve faced adversity – even in-game – Celtic have usually responded. Postecoglou said: “Resilience as a team is important.
“For a lot of this season we’ve got off to quick starts in games and got the first goal.
“From there you can dictate. But there are games when that doesn’t happen and it’s important that you react in the right way.
“And in the big games this season, we’ve reacted in the right way.
“Both in the League Cup Final and the derby at Ibrox, we got back in the game quickly and made sure that conceding a goal didn’t face us in terms of how we want to play our football.
“It’s great to see the players have embraced that aspect of it because it does give you confidence and belief.
“As well as I prepare them for the game, you don’t know how it’s going to go, what’s going to transpire.
“We keep saying to the boys that whatever the challenge may be, whether it’s early or late in the game, we have the tools to overcome it.
“The players have gained confidence from the fact we’ve been able to do that in different ways in games.”
One player who has personified that has been on-loan centre-back Cameron Carter-Vickers, who bagged the winner against Rangers last time.
His composure and steely determination has spread throughout the team and the manager is delighted with his contribution since he arrived from Spurs in the summer.
He said: “Cam’s been great. When I did my research, I looked like a type who could provide leadership at the back and that’s how it has provided.
“But there’s still enormous improvement in him. To defend, he’s young and wants to improve.
“I go for low-maintenance players like Cam because it makes my life easier.
“He wants feedback and works closely with our coaches. He has an inquisitive mind so he gives an opinion on how things are going. He’s a good part of the group – not just as a footballer but as a person.”