Not the 2002 World Cup, mind. That was a blast. It’s the rupture that preceded it on the largest of the Northern Mariana Islands that gets under his skin.
Next Monday will be 16 years to the day since ‘IT’ happened and still a nation hasn’t quite let go.
“I’m sad that’s what people reference all the time,” said Duff yesterday. “Any lad now that writes a book, they have to have a chapter on Saipan. It’s embarrassing. So, yeah, for me it was the World Cup, not Saipan.”
At its most basic level, Roy Keane’s dramatic exit deprived Ireland of their talisman and one world-class operator.
The Manchester United general had been the driving force in the qualifying campaign but he wasn’t exactly a giant among pygmies.
As with all the best Irish sides, it is only with the benefit of a rear-view mirror that the ’02 squad has been truly appreciated.
Mick McCarthy still had Duff, Robbie Keane, Shay Given and many more of the kind that Martin O’Neill would dearly love at his disposal now.
The common regret, uttered again yesterday by Eamon Dunphy, is that an Ireland side with Roy Keane in the middle, could have drawn designs on maybe even winning a weak tournament that produced semi-finalists from Turkey and South Korea.
Duff has a different take on that alternative history.
“Yeah, and Spain weren’t one of the great Spain teams but we dominated them and then went to penalties.
"But, looking at it from another point of view, Roy dominates dressing rooms and people were in fear of Roy. Not me, not Robbie. He looked after us because we were young and fearless.
“But even at Man United people were in fear of him. In a way, when he left, it let lads breathe in a way. We’ll never know.
"He could have driven us to the final but also, other players that maybe played well might not have played as well because Roy was barking down their neck for 90 minutes.”
Duff was renowned for his love of the leaba during his time with the Irish team and that laidback approach to events off the pitch seemed to pay dividends in Saipan at a time when the squad was in crisis mode and the island of Ireland divided into two camps.
“It’s only when you come back home and you realise that the country comes to a standstill. But the sideshow didn’t bother me.
Myself, Robbie, Richie (Dunne), we were just young, fearless. We didn’t give a fuck what was going on. So, whoever wanted to leave the squad could leave the squad. Grand.
"I was just, you know ... meetings, crisis meetings, ‘what are we going to do?’ I wasn’t listening. I was just thinking, ‘What am I going to do in the first game against Cameroon?’
“So, whether it was Roy, Niall (Quinn), Steve Staunton, whoever, I just wanted to go and play football.”
That he did. Duff’s goal against Saudi Arabia in Yokohama, the third in an emphatic 3-0 win, wasn’t exactly a thing of beauty — “shit goalkeeping,” he said — but the Japanese-inspired celebration that followed was one of the tournament’s iconic moments.
The sad thing is that the Republic have had none to frame from the global gathering in the years since.
Duff spoke yesterday about Italia ’90 and USA ’94 and how they had overloaded his senses. Inspired him.
Kevin Sheedy was already a god in his house and the 11- and 15-year-old Duffer thrilled at the magic created by Roberto Baggio, Hristo Stoickov and Romario.
“That summer of ’94 I was six stone with scraggy hair and whiter than that (concrete) wall over there but I thought I was Romario for the summer. That’s who I was when I played out in the street. I was always trying to toe-poke finish.”
It’s why the kid in him would love to see Lionel Messi drag Argentina all the way this next few weeks and why he worries at the ongoing failure of the Irish national side to qualify for a tournament that is still the greatest show on earth.
“If you’re looking from an Irish sporting point of view, what’s our successes? A kid is going to want to go out and play rugby, not football.
“They’re going to want to watch the Irish rugby team, the Grand Slam just gone.
“They’re not going to sit in and watch us against the USA or us against France (in recent friendly internationals). I hate to say it but you’re going to play the PlayStation. That’s the truth of it.”
He’s not the only one to see the promise in Declan Rice while Graham Burke’s appearances against the French and Americans have shown that players can fail to make the grade in England, return home and still play for their country.
Duff admires the Shamrock Rovers player’s honesty in looking for the ball but he doesn’t see him fashioning a regular berth for himself in O’Neill’s XI until he returns for another shot at the UK.
A coach with the Rovers U15s, it was put to Duff that the sight of one of the club’s senior men in the senior ranks must at least have put an extra pep in the step of his charges and others like them in the academy ranks.
“I haven’t had much contact time with my lads because they’re doing Junior Cert and what have you. Maybe it inspires them but they shouldn’t need that.
"They’re with me and they want a career. I’ll drive them and they shouldn’t need Graham Burke to inspire them.”
All isn’t lost, then.