A world of pain for O'Donnell
This was a day when World Cup dreams were supposed to be shared, not shattered.
On a perfect, sun-dappled August afternoon, a dark cloud hovered over the distraught figure of Tommy O'Donnell and only a heart of stone could remain unmoved as the Munster flanker lay prone for five minutes on the Millennium Stadium turf.
As he clutched, in visible agony, at Dr Eanna Falvey's jersey while being wheeled from the fray, his fellow professionals could not help but suffer the pangs of intense sympathy for their stricken team-mate.
A day which had been unveiled ostensibly as a series of individual battles between a host of players seeking to earn the right to become World Cup contenders had been forgotten as each were suddenly stunned into a requiem for a fallen friend.
Of the few pockets of Irish support on the snaking streets of Cardiff city centre, there were few appraised of medical knowledge but pure instinct informed them that the prognosis for the Tipperary man was not a positive one.
Like the players, there was an almost inexpressible sense of grief for one of Irish rugby's most popular characters and, as he had proved in the time he had spent on the field, someone capable of providing the X-factor needed to spark any side.
If anyone can even threaten to appreciate the anguish that O'Donnell must be experiencing during these fraught moments, then Felix Jones, his club colleague, is intimately appraised of such torment.
Four years ago, against France, his World Cup dreams were violently extinguished in a shocking instant.
One minute a giddy candidate for inclusion at world rugby's global festival, the next another casualty of this occasionally and indiscriminately ruthless and violent sport.
"Yeah of course," Jones said quietly when asked whether his own personal memories came flooding back as he and his team-mates watched in horror as O'Donnell was rendered immobile after collapsing beneath the weight of his own bravery and the awkwardly falling Alex Cuthbert and James King.
"We don't know what the full story is there but my heart goes out to him. Hopefully it's not as serious as it looked. There aren't a huge number of people who have gone through what he could be experiencing now and there are no words that can describe it really.
"At the time four years ago I knew immediately it was gone. I tore a lisfranc ligament in my foot and I knew straight away. You put so much work into it so it was massively disappointing. It's hard to describe."
Jones has experienced an improbable range of injuries already in his career; in 2011, the one that coincided with him missing the opportunity to feature in that year's World Cup arguably was the nadir. But he did recover.
"I think you do. It's certainly very difficult, just time I suppose, it's different for different people. You get past it. Massive setbacks like that, massive injuries in people's careers, can help build character and help define it."
Ireland's captain Jamie Heaslip had unveiled surprising emotion a day earlier when it was revealed to him that he would become his country's most capped back-rower against Wales; his immediate thoughts had turned to David Wallace, the man whom he had eclipsed.
Heaslip knew he would do so only by virtue of the fact that Wallace - like O'Donnell a Munster openside - had seen his career end during a World Cup warm-up game for the last tournament, when he was cruelly stricken by a Manu Tuilagi tackle.
"I was a bit sad to be honest, that I passed one of my idols, and especially in the last World Cup he was one of the guys that I unfortunately saw him play his last international. Yeah, I was pretty sad to be honest. And it's bitter-sweet to be hearing that."
His emotions now have another sad tale upon which to drape themselves.
"You never want to see a guy coming off the field on a stretcher," he said wanly, post-match. "He was having an excellent game, every time I looked up he was hoovering up any loose ball and being really well defensively. Lads pick up injuries and bangs, it's not what you want to see."
Joe Schmidt shared amply in the concern.
"Tommy made 14 or 15 tackles, won two or three turnovers and as he fatigued, he picked up a couple of penalties. He's such a dynamic player and had started really well so we'll cross our fingers and wait and see."
The numbing sense of shock precluded any definitive sense of the damage that had been wrought; it was if the players, like O'Donnell's supporters, are hoping against hope.
"I'm not sure how bad it is yet but he was in a lot of pain coming off," admitted Mike Ross. "It's a sickener. He's a really popular member of the squad. So fingers crossed but it's a tough one for him.
"You can't think about it, if you look at how it happened, it was pretty innocuous. He just took the ball up and there's nothing you can really do to prepare for that.
"But if you go out and try not to get in trouble, that's when you get injured so you just have to go as hard as you can."
The cruel irony is that O'Donnell, a proud son of Cahir with a hurling and football background who only developed his rugby talent as a 14-year-old in Clanwilliam, had only recently recovered from a two-month hamstring lay-off.
He was uncoiled and ready to burst forth once more and, although dropped after starring against Italy in the opening game of the 2014 Six Nations, reinforced by a breakaway try that demonstrated his prodigious turn of pace, there was a genuine sense that he could edge Jordi Murphy from the inordinate queue to fill the available back-row slots in Schmidt's 31-man squad.
We now may never know if that may have been the case.
Jones, again, is someone to whom O'Donnell, even at this bleakest of removes, can accede to in what may seem like the vainest attempt to eke some optimism from his despair; he will be 32 when 2017 comes around.
Time, just, is on his side.
Jones learned to forget. It took time and patience but now he is looking forward to, he hopes, this World Cup.
"Personally no, I never felt I had to make up for something now. I put that injury behind me a long time ago.
"But that doesn't mean I don't want to make this squad of course, absolutely not. I'll be pushing as hard as I can to get in this time."
Life will push on, as it must; Schmidt reminds us that players will suffer if they are spooked by what he terms the "uncontrollable variables".
For all the empathy within the squad, there is a ruthlessness that resembles an army on the march; they keep driving on. No individual can trump the collective.
"Everyone is pushing their own cards forward but, at the same time, everyone is aware that it's our contribution to the greater group that's going to be of more value," added Jones.
"I'd love another chance, of course I would. But I'm not too sure what's going to happen next week. I don't think anyone is, including you guys."
Sport, such a capricious mistress, once again doled out a distressingly familiar reminder of this fact to all of us.