Tommy Bowe's searing try six minutes from the final whistle might've been the streamlined product of hours of work on the training pitch, but this success which tested the players' self-belief to the core was less about playbooks and more about an often-dismissed old-fashioned virtue.
In the occasionally automated professional game, where the emphasis tends to be on tactical and physical preparation, character is not always high on the agenda, yet the denouement in London said much about Ireland's atttitude.
With the result clearly slipping from their grasp, and with Brian O'Driscoll carried off on a stretcher following a sickening collision with Paul O'Connell's knee, you wouldn't have given much for Irish prospects when Jonny Wilkinson kicked a replica of the drop goal that won the 2003 World Cup to give England a 16-13 lead.
However, the sort of hard-nosed determination that was so conspicuous by its absence at the Stade de France was coursing through the players' veins this time. O'Connell delivered a line-out off the top, Tomas O'Leary took the ball at full tilt and Bowe's devastating angle did the rest as Wilkinson, Ugo Monye and James Haskell were left grasping.
Of course it was perfectly executed rugby-by-numbers, but to have the necessary composure to pull off a play under the gun was a sign that the psychological scars from the France defeat had healed. It was the ultimate triumph of character.
"We just weren't going to give up. Three points down with less than 10 minutes to go, we came back, scored a really good try and won the game. So, that's a great feeling," said O'Connell.
While it wasn't a classic - a torrential downpour in the first half saw to that - it was still a fascinating physical battle which swung both ways before Bowe burst through that yawning gap to provoke joyous celebrations among the Irish contingent in the 82,000 crowd.
With unbeaten France on course for a first Grand Slam since 2004 after their 26-20 win over Wales in Cardiff, Ireland's hopes of retaining the championship are slim, but with home games against Wales and Scotland to come, the chance of keeping the Triple Crown remains as an incentive.
England might've been one-dimensional in their approach, but the Irish defense was heroic with Stephen Ferris and Jamie Heaslip making a major impression. In the end, the swarming green jerseys pulled off a staggering 99 tackles and only missed one.
If there was a logic to the selection of the in-form Jonny Sexton in place of Ronan O'Gara, coach Declan Kidney had courted controversy by going for Donncha O'Callaghan in place of the impressively consistent Leo Cullen, and by starting Geordan Murphy who had only played three club games all season.
This was all incidental as far as John Hayes was concerned. The first Irish player to win 100 international caps predictably looked a little uncomfortable as he ambled out onto the pitch ahead of O'Driscoll, but there was a definite flicker or two of emotion from the big man during Ireland's Call. "All the team were really motivated for John, to make this a special day for him and his family," added O'Connell.
As if to demonstrate that this was a test match like any other for the first Irish player to win 100 caps, Hayes was soon penalised for dropping a scrum, but that was a temporary blip in the first half anyway as England were woefully prone to turnovers and from one of their initial mistakes, Bowe plundered the first of his tries after a textbook Sexton grubber kick.
The rain began to fall as the game descended for a while into a miasma of knock-ons and general mistakes, but with Ferris creating his own brand of havoc at the breakdown, and with Wilkinson struggling to exert any control for England, Keith Earls' try following a bizarre call by assistant referee, Christophe Berdos, gave Ireland the cushion they deserved.
However, with redemption at hand following the bitter disappointment of Paris, things began to unravel with alarming speed. First, the young tight head, Dan Cole, got the vital touch beneath a pile of bodies, then O'Driscoll was the victim of friendly fire, before Wilkinson put England in front for the first time.
O'Gara, on in place of Sexton, prodded Ireland forward and with the championship hopes on the edge of a precipice, O'Connell, O'Leary and the jet-heeled Bowe did the needful. A try geometrically conceived, but dredged up from the heart.
France may be motoring on to their destiny, but Ireland demonstrated the sort of never-say-die attitude that keeps them in the race. Character, after all, is alive and well in international rugby.
"A major thing is how you respond to adversity," said Kidney. "We didn't play as well as we could in Paris and it turned out to be a tough day. But this time our defense held up when they had chances, and on the other side, we were able to make the most of our chances."
Three tries to one, a win over the old enemy. It was good to be Irish in London last weekend.