It was yet another pinch-yourself moment in a career that is becoming increasingly full of them.
Speaking to the YEP last Thursday after training, Cooper was in fine form, with good reason.
He bounced back into Thorp Arch after playing his part in a famous Hampden Park victory for Scotland, securing a home World Cup play-off semi-final.
“It was unbelievable,” he said. He uses that word a lot.
“The place was bouncing and to beat Denmark is not easy. We can take a lot of confidence from it. That’s six on the spin we’ve won now going into the play-offs and we’ve got that all important home tie.”
The Scotland camp ended with a ‘nice drink’ together although nothing on the scale of the socialising Dom Matteo talks about when reminiscing his era with the Tartan Army.
“I think Dom maybe ruined it for our generation to be honest,” Cooper added with a wry grin.
When he entered the international scene in 2019 to win the first of his 13 caps, Cooper had no difficulty in fitting in as a new boy and credits his fellow players for that. He’s grown close to Liverpool’s Andy Robertson and Aston Villa’s John McGinn but insists the group as a whole make life easy for newcomers.
At Leeds, wearing an armband that adorned the biceps of men like John Charles, Billy Bremner and Gordon Strachan, the group dynamic is his responsibility.
“Marcelo lets us school that, the dressing room is ours,” said the defender.
“I’m sure if anything did get out of hand, which it never has, I could go and speak to Marcelo and he’d lay down the law.
“But he leaves the dressing room to us, he wants us to be together and we are, as together as we’ve ever been. We get on like brothers, it is like a brotherhood. It’s unbelievable to be part of.”
Cooper first began to learn how a captain should lead at Chesterfield, where he resurrected his career after his release by Hull.
“Ian Evatt at Chesterfield was probably the first real captain I had,” he said.
“He’d been promoted to the Premier League (with Blackpool). He came back down to League Two under Cooky (Paul Cook) and he was brilliant with the lads, a massive leader, always had time for you.
"If you made a mistake he wouldn’t come after you, he’d just explain to you. A great fella. I really got on with him, I’m still in touch with him to this day - tapping me up for the young lads at Leeds.”
Ask Cooper’s team-mates from that side and they all say they saw leadership in him, if not the maturity he has added since, partly out of necessity given the Massimo Cellino era he walked into in 2014.
“I’ve matured a lot, I’ve seen a lot,” Cooper told the YEP.
“The early days at Leeds were tough, I had to really dig into my inner self and try and get over those tough times. I came in for a bit of stick, rightly so, I didn’t perform anywhere near as good as I can.
"Those are moments you have to go through in your career to gain that confidence and that respect from yourself. And I like to think I’ve proved a few people wrong over the years.”
Better times followed with the arrival of Marcelo Bielsa, under Andrea Radrizzani’s ownership, but it has not all been plain sailing.
Play-off heartache hurt everyone at the club and when a 2019-20 season that was going brilliantly was abruptly interrupted by the Covid-19 pandemic, the squad needed leadership and one another.
“We had won five on the bounce and the spirit was so high in the camp,” he said.
“To hear all the rumours that the season was going to get curtailed, panic set in. Everyone struggled at some point and felt the lowest we’ve felt. It was a tough moment in anyone’s life.
“We went out of our way to get on the WhatsApp groups, Facetime and get stuck into each other. We had a programme, I’m not going to lie, it was hard.
"You had them ‘can’t be bothered’ days but you found a bit of strength in the group chat. You’d see the lads messaging, they’d been out and done theirs and we pushed each other on.”
Other situations that require his leadership are private affairs.
“The side people don’t see is that we’re human as well, we have feelings, we have problems like every normal person,” he said.
“I like to think I’m there to pick up the pieces sometimes when lads are having tough times, maybe the foreign lads’ family members aren’t well and they’re away from home, things like that.
“You’ve just got to try and help people out, be a normal person.”
Cooper counts his dad Dave along with Stuart Dallas and Luke Ayling as confidants but insists he could go to anyone in the squad over a personal issue.
“That’s the environment we’ve created,” he said.
“It hasn’t happened overnight but that’s the way it’s meant to be.”
A core group of senior players have stayed long enough to establish a culture and a social circle. Cooper says his other half Abbie has played a part, sorting out group chats for the players’ partners to foster a family feel, something that took on extra importance for new arrivals unable to easily develop friendships due to Covid restrictions and guidelines.
There are leaders coming through the ranks, too.
“Charlie [Cresswell] is definitely right up there,” said Cooper. Pascal [Struijk] has got it in him. He’s not the loudest but he sets a good example. There’s Joffy (Joe Gelhardt).
“They’ve all got a lot of character and they’re all going to go a very long way with Leeds. The potential is there. It’s just consistency at that age.
"I always struggled a bit when I was younger. You can maybe have one or two good games then not be at your best. But they’re all great lads, they want to learn, they take it on the chin.”
At 30, Cooper himself is still striving for consistency and wants to learn. He rates his Premier League form as ‘up and down’ against players who punish any little mistake, in a way Championship forwards did not.
“The intelligence of players, the pace, their power, it’s tough,” he said. “I’m still learning but I’d like to think I’ve held my own.” It’s been a crazy two years for me.
“I’m just riding that wave, trying to take everything in.
“It’s taken a lot of sacrifice, sacrifices I’m glad I made but what football has brought to my life is unbelievable.”
There’s that word again. His story warrants it. It’s not so long since captaining Leeds in the Premier League, battling with Kane and making the World Cup play-offs were entirely beyond belief for Cooper.
So when he vows to put his head down and work hard so he can keep improving, he’s entirely believable.