You have to absorb the enormity of the outcome, recognise its place in history and appreciate the effort that went into producing it.
Ireland had just beaten world champions New Zealand, breaking their 111-year winless streak, and doing it in style.
They had put five tries past the most feared side in world team sport, to end their record-breaking 18-game run of consecutive victories, stretching back to before their World Cup campaign in 2015 - and in doing so, became the first team to score 40 points against the All Blacks since the mighty Springboks at Ellis Park in 2004.
Throw in a neutral venue at Chicago’s Soldier Field, in a city celebrating the end of the Cubs’ 108-year World Series curse, and a sold-out record crowd of 62,300, dominated by delirious Irish supporters, and it all made for a very special day on the shores of Lake Michigan.
So much so that even Joe Schmidt, Ireland’s most detail-oriented of head coaches, promised this was one performance he would not analyse too deeply, although you can be sure that by the time the IRFU travelling party touched down in Dublin at 5am today, he will have watched the game video two or three times and collated a dossier of work-ons for his players.
Even a resounding first victory over the All Blacks was not without flaws.
The way the New Zealanders fought back from 30-8 down, after an exhilarating first 50 minutes from the Irish, to make it a four-point game with a quarter of an hour to go at 33-29, suggested Ireland had been mistaken in thinking they had learned the lessons of their devastating defeat to the same side on home soil in 2013.
Yet one of the traits that marks this side out from those that went before is precisely the reason Schmidt will present them with his dossier for further improvement, safe in the knowledge they will devour its contents and come back hungry to put them into practice.
The lessons of three years ago and that heartbreak at the Aviva were learned and game by game since then had been building blocks to the performance Ireland delivered on Saturday night in Chicago.
Kieran Read: “We weren’t allowed... weren’t able to get into the game”
After just their fourth defeat since the 2011 World Cup final, All Blacks captain Read was spot on in his assessment of a first half, that while poor from the back-to-back world champions, was the result of the pressure applied to them by a ravenous Ireland team.
New Zealand had actually taken an early lead at 5-3 when, ominously, wing Waisake Naholo had carved Ireland’s midfield apart, scything through the otherwise immaculate Robbie Henshaw, Jared Payne and full-back Rob Kearney before Simon Zebo hauled him down, the ball initially halted by CJ Stander but bouncing off Kieran Read’s face into George Moala’s path, although Beauden Barrett missed the conversion.
Yet, as in 2013, Schmidt’s side would soon take the initiative, and, if anything, looked more rounded, organised and composed than they had been in that wonderful first period of three years ago. Then, they had raced into that 22-7 interval lead, this time it would be 25-8.
Aside from the ferocity of the breakdown, spearheaded by a wonderful tight-five effort, and the clinical finishing that marked both periods, there was air of confidence that when mistakes did happen, the Irish were not going to panic.
If one player made an error, his team-mate made amends and when they did come under pressure, they did not crack.
They were also taking another leaf out of the New Zealand mindset by punishing opposition weaknesses with ruthless efficiency.
New Zealand indiscipline would be rife throughout the opening half, not least when loosehead prop Joe Moody was carded for a spear tackle on Robbie Henshaw.
Ireland would make the most of their power play.
Joe Schmidt: “Sometimes it’s character more than cohesion and that was evident”
With Moody in the bin, Ireland seized their chance, Jordi Murphy, who would suffer a serious-looking knee ligament injury on 26 minutes, and Stander powering over as the forwards took full advantage, exposing a frail lineout and mauling a weakened pack to great effect, aided and abetted by some immense tackling by Henshaw.
With a man down, New Zealand conceded 12 points and scored none and Ireland were back in front at 15-5.
A try apiece either side of half-time from Munster’s Conor Murray and Simon Zebo, both putting in their strongest performances in an Ireland jersey when it mattered most, had given their side further insurance, pushing the lead to 30-8 but against the All Blacks you can never have enough cover.
Ireland knew that and when the fightback came, with three quickfire tries, all converted by Barrett, through TJ Perenara, Ben Smith and replacement debutant lock Scott Barrett, the younger brother of Beauden, the game seemed to be unfolding in eerily similar fashion to the 2013 encounter.
The superb Murray had kept his nerve when temporarily taking over the kicking duties, sending over a penalty as Johnny Sexton was being treated for the cramp which would hasten his departure and pave the way for Test debutant Joey Carbery, further increasing the sense of dread that Ireland would not hold out, the 21-year-old entering the fray on 58 minutes with the score 33-22.
New Zealand closed the gap further within minutes through Scott Barrett to make it a four-point game as the All Blacks upped another gear and Ireland looked well and truly on the ropes.
Rory Best: “We needed to get the ball back and keep it”
Holding a slender lead, a repeat of 2013 was on the cards, Ireland having gone into their shell and paying the price for trying to protect what they had. As they regrouped for the restart at 33-29, captain Best looked around at his players and knew things had to play out differently.
“We just talked about how we had to keep attacking them and when they put us under pressure we didn’t want to dive into lost causes in the ruck, we needed to keep our defensive shape but we needed to get the ball back and keep it,” Best said.
“Over the last three or four years we have looked dangerous when we get ball in hand. We needed to use that kick off as a chance to attack them again, don’t sit back and hope that we’d win the game.”
Schmidt: “We were not going to revisit what happened three years ago”
The determination of captain and coach was also coursing through the rest of the team and instead of shrinking they grew in those final 10 minutes, just as Best had hoped.
The build-up to Henshaw’s winning try was the eptiome of that spirit and also the hallmark of a world-class group of players.
A brilliant pass from Payne out to Zebo, who chose not to kick for safety, as may have been the Irish way in 2013, but to apply some more pressure, his thumping left boot aimed directly at the out of position replacement flanker Ardie Savea, filling in at wing with New Zealand stretched by injuries. Ardie passed inside to his brother, Julian Savea, who should have booted clear but thanks to a superb kick-chase from Ireland found Murray looming into view.
He panicked and tried to run his way out of trouble but the Ireland scrum-half hunted him down in the in-goal area and with Andrew Trimble in support they bundled him out to give their pack a five-metre scrum.
It was the foundation for the try that would put the game beyond the world champions. Jamie Heaslip launched himself off the base of the scrum and slipped the ball inside to the hard-running Henshaw, who powered his way over the line, no more fitting a winning try scorer.
Test rookie Carbery nailed the conversion and at 40-29 had the luxury of missing a 79th-minute penalty. Ireland really were in dreamland.
B Smith; W Naholo (A Cruden, 59), G Moala (C Taylor, 72), R Crotty (M Fekitoa, 26), J Savea; B Barrett, A Smith (TJ Perenara, 45); J Moody (O Tu’ungafasi, 60), D Coles, O Franks (C Faumuina, 60); J Kaino (S Barrett, 46), P Tuipulotu; L Squire, S Cane (A Savea, 60), K Read
R Kearney; A Trimble, J Payne, R Henshaw, S Zebo; J Sexton (J Carbery, 59), C Murray; J McGrath (C Healy, 61), R Best (S Cronin, 71), T Furlong (F Bealham, 57); D Ryan (U Dillane, 65), D Toner; CJ Stander, J Murphy (J van der Flier, 26), J Heaslip.
K Marmion, G Ringrose.
M Raynal (France)