That August Saturday in 2021 when Mayo rendered Croke Park a boneyard for Dublin’s seven-in-a-row ambitions – the towering theatre of dreams reimagined as a cemetery for Sky Blue invincibility – embedded itself on the hard drive of a team for the ages.
The ending of their 45-game, 2,540-day unbeaten championship run introduced these players to unfamiliar music, what Sebastian Barry calls "the dark choir of pain".
Brian Fenton, who, against Mayo, was – remarkably - enduring a first championship loss in a career that had already yielded five All Stars and two Footballer of the Year gongs, hinted at the effect ten weeks after their fall.
The midfield godfather found himself submitting to “a lot more introspection, just thinking of your own game and where we’re at – and I think that’s the case across the group.”
Six months later, after Dublin’s lost immunity to gravity was confirmed by relegation to Division Two, Fenton would speak again, even more forcibly.
“There’s probably just a bit of a chip on our shoulder. We’re certainly hungry for more success despite all the years of success that we’ve had.”
Here is a storyline that has been scarcely examined as commentators mine into the quarry of data in search of some nugget that will assist them in calling Sunday’s latest summer joust with Kerry.
Dublin are angry and ravenous and ready to spit fire.
It is undeniable that there are lingering concerns – eye-catchingly poor league form, the lack of a meaningful challenge this summer, potential defensive vulnerabilities against an alpha Kerry attack, and, mostly, grave concerns about the fitness of Con O’Callaghan and James McCarthy – but fears about their enduring appetite are not among them.
A team with unrivalled champion pedigree, a dressing-room that is a storehouse for the better part of 100 Celtic crosses, is fuelled by the hunger normally only associated with squads who have lived for too long on the sporting breadline.
Two of the team’s leading figures informed your correspondent that lifting Sam Maguire this year would be “sweeter” than anything that has gone before in their storied careers.
That is some mindset set against a back catalogue of achievement that includes the smashing of just about every landmark in the old game’s history.
Why are Dublin indignant? Their irritability is drawn from several wells.
A frustration that they allowed themselves fall below their own Himalayan standards on and off the field in 2021.
Exhaustion and controversy and Covid distractions buffeted the squad, but, still, there is an internal conviction that they did not exhibit their true face to the world. There is a wish to set the record straight.
As natural-born competitors, something stirred in their blood as they read their own sporting obituaries and, the rush by some to stray into RIP.ie vocabulary.
It was particularly grating to those leading figures who remain in their mid-to-late 20s, the prime of their athletic lives.
As the form of Ciaran Kilkenny, Fenton and, when fit, O’Callaghan has illustrated this summer, these all-time greats remain in perfect harmony of body and mind.
Their impatience to prove the point to a wider audience amounts to a significant weapon in their armoury.
Players will search for grievance if it can be converted into competitive edge.
One player admits he even found some psychological juice in oddsmakers’ lists that elevated Kerry ahead of Dublin in the All-Ireland betting for the first time in a decade.
To borrow from the towering American writer Don DeLillo: “History [is] a force to these men, a presence in the room.”
It is true that there were days during the league when the search for the old invincible Dublin seemed as futile as trying to find light emitting from a dead star.
True also, that there is ample evidence to support the thesis that David Clifford and Kerry’s time has arrived – even if that places a heavy burden of pressure on the Kingdom to deliver on huge expectation.
It was a burden they were ultimately unable to shoulder against Tyrone last summer or Cork the year before.
Kerry have long clung to a belief that the critical difference between in many of their recent duels with Dublin was the inestimable presence of Stephen Cluxton and his choreographing of Sky Blue patterns of play.
In an attempt to gain a psychological foothold they will look to fiercely interrogate Evan Comerford’s kick-out strategy.
Jack O'Connor will relish every opportunity to probe for weakness in a Dublin defence denuded by injury and the ticking clock, one in urgent need of McCarthy’s leadership, aura and physical presence.
Without McCarthy and O’Callaghan, a steep semi-final incline assumes the dimensions of a murderous incline for the Leinster giants.
Against that, they can call on that champion spirit and a deep craving to show, one more time at least, the best of themselves.
Anger, as John Lydon barked all those years ago, is an energy.
For all the magic in Dublin's feet, it might be the chip on Fenton's shoulder that represents the great peril to Kerry's pursuit of old summer certainties.