There is an old saying in sport that suggests the referee has had a good game when you don't notice him. Last Saturday Ireland had a right to be aggrieved with the English official's performance, especially when he penalised a driving maul just metres shy of the Welsh tryline in the dying moments of the game. Ultimately the presence of Wayne Barnes on the park was not the chief reason Wales won and Ireland lost.
The result was also determined by one side having a better defence, a better lineout, and a superior half-back combination. Ireland huffed and puffed and played with heart, but Wales used their heads. That counts.
So did the blistering start they got off to. Dominating possession, Wales forced Ireland into mistake after mistake inside the first 13 minutes, won four penalties, all of which were converted by Leigh Halfpenny.
Everything they tried came off. In attack, their kick-and-chase policy, a tactic Ireland had successfully used in their three previous games in this competition, worked a treat.
And in response, Ireland panicked. Their restarts were poor, as was their handling and their indiscipline, allowing Wales establish that early twelve-point lead. "We just never caught up," said Paul O'Connell.
They did try. The stats show they had 66 per cent of territory, 64 per cent of possession, that they carried the ball 185 times compared to the Welsh who ran with the ball on just 94 occasions.
But when opportunity knocked, they choked under pressure. Four times they turned down opportunities to kick for the posts via penalties. Only once did fortune favour the brave, when Sean O'Brien led the driving maul from a secured line-out to win a penalty try.
With the benefit of hindsight, had other decisions been taken, Ireland could have scored another nine points, could have won by two. Instead, there was a rush of blood to the head. What could go wrong, did go wrong.
At lineout time, Rory Best - normally so reliable - failed to find his man with his first two throws and with four in total. He wasn't the only decent player to err: Rob Kearney knocked on after Jamie Heaslip had sent him clear in the first half, while Jonny Sexton missed a kickable penalty in the 15th minute when Ireland were scoreless.
Hampered by a hamstring injury, Sexton clearly wasn't himself on Saturday - and by extension - neither were Ireland.
Despite factoring all these issues into consideration, they should have won. They should have taken advantage of Sam Warburton's presence in the sin-bin, after Barnes had sent him there for illegally using his hands at the breakdown.
But they didn't. Instead the Welsh performed heroically in spite of their numerical disadvantage, coughing up just six points in the timeframe their captain spent on the sideline, while landing a bonus score via Dan Biggar's drop-goal.
Their resilience then was a taster for what was to come later, when Ireland delivered wave after wave of attack, going through 44 phases in two separate passages of play from the 50th to 56th minutes, without scoring. Four minutes later, Scott Williams did score. "And that was a key turning point," admitted O'Connell.
So the door to their grand ambitions got slammed shut and the frustrating elements of a defeat were left to linger.
Then someone mentioned to Joe Schmidt that there was still a Championship still to play for, a prize worth winning, one Ireland have secured just twice in the last 30 years.
No longer favourites - England carry that burden - they actually have a wonderful chance because irrespective of the points advantage England currently possess, Ireland have an easier game.
That's distinctly different from saying Ireland have an easy game. They don't. Scotland, despite losing four from four, are improving and at Twickenham, they rattled England for long spells.
The French may be mediocre by their lofty standards, but the sight of a red rose on a white jersey will fire their imaginations. "The important thing in these scenarios," said Schmidt afterwards, "is to concentrate on just winning the game."
That, believe it or not, could be enough.