From shaking with nerves at Everton to commanding displays at Brighton, the centre-back is now a crucial figure for club and country
As a teenager, Shane Duffy used to shake with nerves in the early stages of Premier League matches with Everton.
He has no such worries these days, with his emergence into a Premier League regular with Brighton and key player for his country the big Irish success story of the past 12 months.
That was rewarded on Sunday night when he was named Senior Player of the Year for 2017, news that came as surprise to Duffy who learned of his success while playing cards with David Meyler after snow grounded their flight in Manchester.
"I was shellshocked," he confesses. He expected James McClean to get the nod, and it appears that his fellow Derryman shared that view. Duffy jokes that McClean was raging, before confirming that the winger would have received his vote.
Still, he was happy to take the prize as a reflection of his progress, with this week's trip to Turkey making the 26-year-old feel like an established member of the group because there are so many newcomers.
Martin O'Neill gave him his first cap in the summer tour to the USA in 2014 which featured a much-changed squad, and Duffy can see the similarities in this group except he's in a different bracket.
He says that he continues to feel like a newbie, although the assembled media did get to hear Duffy chiding Roy Keane for a poor ball aimed his way in a shooting drill on Tuesday. It's hard to imagine any of the eight newcomers having the confidence to shout 's**t pass' in the direction of Corkman.
"I nearly forgot who I was speaking to when I said it," he laughs. "Ah it's just being comfortable. I shot it over the training fence anyway. He's good with me, and good with everyone, and it's great that you can have a bit of banter."
Keane's reply, for what it was worth, is that his pass might have been bad but Duffy's control made it look worse.
Management realise they are operating with a more assured performer these days, though, with his club education benefiting Ireland.
He was a different animal altogether when breaking through at Everton, a time when he was best known for his near death experience in 2010 while trying to impress Giovanni Trapattoni in a training game.
That story is well told at this stage, but he has rarely spoken about how he struggled when David Moyes gave him a chance at the highest level.
"When I played at Everton the first time, I was purely raw, I'd just come out of Derry and I was shaking when I was playing," said Duffy yesterday.
"For the first five minutes, you're shaking and you don't even want the ball. When you get your first header, you feel better about it all. But the first five minutes you're thinking about everything, where you are positioned, and looking around everywhere.
"Now I'm just calm. I feel like I belong there. It's a nice feeling to go out knowing you can compete with those kind of players and feel comfortable."
The decision-making has naturally improved through experience. Even in an Irish context, Duffy has left behind the memories of his sending-off against France at the Euros and a rash moment in Moldova that cost his team-mates.
He's still by no means the finished article and his natural physicality means he will always take risks that can go both ways, but he's having more good games than bad with Chris Hughton an influential figure.
The working relationship has been good for both of them. "He's unbelievable," says Duffy. "He is just getting better and better and is getting a lot more respect in the game now for what he is doing and he fully deserves it."
A future Ireland manager, perhaps?
"I don't think the Brighton fans would be happy with me saying anything," he replies, with a grin. What about a long way down the line?
"You never know. Obviously Martin's not going to be there forever. But Chris is happy there I think. He isn't getting any younger either so there will come a time, for me, that if Martin did ever leave, it would be great for Chris to come in. He always asks about Ireland when I go back, so you never know in football."
Duffy has no plans to move on from Brighton in the foreseeable future either, although it seems inevitable that he will attract attention if he backs up this season. He is reminded of the new premium on established centre-halves in light of Virgil van Dijk's €78m move and quips that he's only worth £2m at the moment. The reality is, of course, very different.
With Ireland, he is trying to find value from the negative experience of the play-off drubbing against Denmark. It continues to trouble him.
"For the first ten minutes I was a hero and then all of us were villains," he sighs, admitting that it has come up this week amongst those who were part of it. "We talk about it, then just shake our heads.
"If you'd offered us one game at home to Denmark, to make the World Cup, we would have bitten your hand off. We thought we'd done the hard work out there and we scored... but we sat back and perhaps that killed us, we should have just kept to our game-plan. We didn't and that is our fault."
Euro 2020 is the focus now and Seamus Coleman's arrival back onto the training pitch has lifted spirits as well as standards. Duffy makes good-natured references to Coleman's high expectations. "It's great to him back and he's giving off to everyone already," he smiles. "He's just a bit old school. Seamus doesn't take any messers or anything like that.
"Any country in the world would miss Seamus Coleman, and he's been unbelievable with everyone from the new ones to the oldest.
"He is quiet in his own way but he'll make a point of going around to speak to everyone and making sure everyone knows what's right to do here and what's not right."
At the last Euros, Duffy was the rookie open to all feedback. Now, he has earned the authority to dish it out.
Daryl Horgan has backed his Preston team-mate Seanie Maguire to make a big impact in the Ireland team in 2018, as he suggested his in-form team-mate is ready to start international matches.