Analysis - Plucky Irish repay O'Neill for trusting in character
Boys in Green stay true to basic instincts of pride and passion to douse Dragons' fire
The Cardiff choir silenced, the strained efforts of 3,000 Irish hearts suddenly released themselves in blessed exaltation.
The sideline celebrated as if they had won the World Cup itself.
Now they and a gloriously defiant team must endure another, albeit familiar, set of tortures next month.
Shane Duffy, mountainous, echoing McGrath of yore, collapsed in exhaustion. Many more did. This was a night when exertion trumped execution.
Ireland's toil was more persistent, their character more compelling, their honesty gut-wrenchingly endearing.
And when their moment arrived in the heat of frenetic battle, they seized it with the clinical calm of an assassin.
Martin O'Neill sought refuge in that courage as a bankable resource and the players re-paid him; the mutual trust now stronger than ever.
These are the gravity-defying tasks that energise the Derryman and he was always going to resort to familiar tools; blunt instruments, perhaps, but capable of delivering a fatal blow nonetheless.
This was a story of guts and glory; the sub-plots were of one play-maker who started and didn't finish and another who didn't.
The risk in delaying Wes Hoolahan's entrance seeming a smarter move when James McClean combined with David Meyler to force Joe Allen's first-half departure.
Now shorn their best player, the mood music changed and the sport deteriorated drastically; no bad thing if one were an Irish fan.
Buoyed by the momentum shift, Irish confidence grew imperceptibly as did their passing pattern.
Even with Allen on the field, Wales had earned no breakthrough; now it seemed even less likely. And so Ireland crept stealthily towards their moment of stunning conviction.
Wales grew ragged, untrusting without Allen's assuredness, an accurate mirror of what Ireland had been without their own play-maker.
But, with initial containment assured, Ireland's middle men now sought to dictate, marshalled by an invigorated Harry Arter, although, like Wales, much of the play resided in the middle third.
Who would blink first on a night when stalemate equated with doom?
Ireland retained their optimism; Wales sought to revert to a wider game, avoiding the clogged middle and Chris Gunter's forays down the right created a twin of terrors for Darren Randolph's goal as the game lurched into anarchic territory, with howls of anguish accompanying the increasing frequency of feisty tackles.
As the game stretched, so did concentration. Randolph held with a diving save whose currency would, sooner than anyone suspected, soar in value.
When left-back Ben Davies dithered tight to his touch-line, Jeff Hendrick seized the moment and took the opportunity to dink and jink his way to the end-line before releasing a cross as if fizzed from a pistol.
Arter, maintaining his furious energy, sprinted to step over and McClean's shot was launched like a missile. With his right foot.
For a man whose life seems to be lived in perpetual motion, the stillness of his body as he wafted his boot was something to behold amidst the cauldron. Now Ireland had something to hold and the bonus of knowing that they also had somebody who could soon help them hold it, if required. Ultimately, they didn't.
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The gamble not to start Hoolahan, combined with endless depths of energy, would pay off. November will reveal how substantial the reward.
By opting for discretion above valour, spurning Hoolahan, the caged bird of freedom remained on the bench as a suitably physical and imposing template was unfurled to rattle the Welsh.
O'Neill acknowledges that the mode was sufficient unto this fiery night but will not pass muster against more feared opponents over 180 minutes of football; guts and glory can only carry honest souls so far.
Here, buoyed by the freshness of two returning players, he augmented the inclusion of McClean and Robbie Brady by also opting to recall Arter, so recently underwhelming in the desperate draw in Tbilisi. The night offered him belated redemption.
O'Neill would have acutely judged this was not an evening to parade aesthetic inquiries of an opposition; rather an exercise in submission by will, force and mental strength, qualities which remain perennial within his squad, for all their obvious limitations.
Throughout his management career, these are the core elements in which he has predominantly placed his trust. Graft to trump craft. Last night, he needed his players to reciprocate.
Little point in trying to win this game late on if it was already a lost cause; and so Ireland dug in. Wales dominated the ball but did little enough with it.
At times, it seemed easier to hold on to one's hat in a hurricane.
Ireland laid out as expected; Meyler shadowing Aaron Ramsey with McClean on the left, Brady on the right, nominated to be in attack or defensive mode when required.
Initially, it was more the latter.
Soon, though, Daryl Murphy's isolation was becoming evident and Wales were pressing more effectively, allowing them to also dominate territory.
Allen, a Welsh Wes, if you will, was orchestrating matters.
And after McClean made one reckless tackle to create a chance that Randolph had to finger-tip over, the early danger signs were evident that Ireland's shape was sundering somewhat.
Wales were creating pretty triangles; their passing as crisp as the evening air, though rarely threatening penetration as the game resided stubbornly in just one half of the field.
Ireland couldn't control the ball; emphasising the glaring fact that the only man who could do so was absent. The Welsh wielded a baton; Ireland a big stick. A Randolph hoof, a Murphy flick-on to nobody.
Their first chance ironically derived from another concession when Meyler was chopped down by Allen after losing control; the visitors had, at least, announced some semblance of threat from the subsequent series of set-piece affrays.
Ireland's anxiety remained to get the ball from one end to the other as soon as possible, if not practical; Arter showed to Ciaran Clark in space but was spurned as another missile rained down on a grateful Welsh defence.
Aside from some elaborate mid-half ping-pong, their defence, too, remained largely unruffled by the hue and cry.
Duffy flashed a shot wide from another set-piece delivery as Ireland sought brief solace in Wales' increasing discomfort with the bobbling balls peppering their area.
The game then changed with Allen's departure, suiting Ireland.
The ageing Murphy plucked from deep reservoirs of energy to persevere while, for Wales, Ashley Williams flung himself forward as his side desperately grasped for belief.
Just as desperately, Ireland gasped for relief.
When Arter's marathon race was run, Whelan came on. O'Neill's faith in his instinct unswerving to the last.
He and his team will need to plot a different path next month. They have shown before they are capable of doing so.