This will hurt. And so it should. Twice in the space of 85 minutes, Ireland managed to blow it.
A totally unnecessary and dangerous challenge from Peter O'Mahony left Ireland short a man for 66 minutes.
"It changed the whole script," said Donal Lenihan on RTÉ Radio 1 after the 21-16 defeat, a record fourth away loss in a row in the championship.
Wales went six points up and later in the game, eight points clear.
But Andy Farrell's side dug deep and displayed what Johnny Sexton described as the "bravery" to get themselves within reach.
It was back to five by the time Ireland won a penalty in overtime. One last chance to secure a draw, or maybe sneak the win and keep the hopes of silverware alive and well.
Then, as sometimes happens in rugby union, the kicker overcooks a touchfinder, trying to eek out an extra yard or two. Disaster, it goes dead, and with it, any realistic hope of a championship for Ireland.
Ronan Kelleher was on the sideline drying off a ball, preparing for the lineout, the final whistle blew, the camera cut to Farrell, whose mask spared lip-readers' blushes.
Agony etched across Burns face as he realised what had happened, this was not the way it was supposed to go.
Sexton said: "We spoke about discipline during the week and that let us down."
Badly. In a game of such narrow margins, madness and sloppiness are always going to be punished.
In the lead-up to both Wales tries, Ireland made s series of errors. Killer mistakes.
And they still nearly won it. Tadhg Beirne and Robbie Henshaw may never play better for Ireland. As a full-back, Hugo Keenan now has no competition for the jersey.
Josh van der Flier, who found himself in the back row because of injury to Caelan Doris, was superb.
"We didn't get to celebrate what would have been a famous victory because some of the efforts collectively and individually were immense," said Farrell. Regret.
There was immediate collective responsibility after the game but the review this morning is not going to be pretty.
Asked specifically about time spent during the week working on avoiding incidents like O’Mahony’s, Van der Flier said: "It would be mentioned, of course, not to give teams entries into the game or field position penalties.
"Most of it is in training, if someone is offside or does something wrong in the ruck that would give away a penalty, it's not acceptable in training so I guess through our practice in training, it’s enforced that way and it is mentioned.
"Penalties do happen, lads can get things wrong and you have to deal with it, but you want to minimise them as much as possible."
How Sexton rocks up after his head injury assessments this week will play a huge part in what happens next. It didn’t look good.
On that subject, France scrum-half Antoine Dupont, who was speaking after watching yesterday's game, said: "We followed this afternoon’s match attentively.
"After the red card we thought the Welsh would walk all over them but the Irish showed their resources, their values.
"They put an incredible amount of energy in, enough to think that they had the extra man.
"It shows the wealth this team have. It’s true, they have had quite a few problems with their leaders, like Sexton, Ryan and O’Mahony but we’ll wait to see the team for next weekend.
"Sexton has been a doubt for games quite a few times but he ends up being on the teamsheet to crucify us when he can. We will prepare seriously all this week."
What hope for Ireland on Sunday? Some.
Bear in mind, Scotland weren’t favourites in Twickenham, Wales weren’t favourites yesterday. Ireland won’t be favourites next weekend.
And if they can channel the hurt that they will have to endure this week then it’s a solid building block for a performance.
"I was saying to the lads that they'll feel sorry for themselves or a couple of hours and bring the best versions of themselves into work tomorrow because there's a lot of us in the group that have been involved in enough Six Nations to know that a Six Nations is not won on the first day," said Farrell.
"From here on in we have to be more clinical and give the performances of our lives to be in the battle to win the competition, it's as simple as that.
"We have a very good French side coming over next week and coming over to the Aviva, and we'll be back ourselves against anyone there."
Van der Flier, who wasn’t injured when withdrawn for Will Connors late on, has earned another start.
Of the French challenge, the Leinster wing forward said: "France looked very dangerous, they're in great form. They're up there with the best teams in the world, but we need a win and we'll be looking to put in a big performance against an incredible team.
"It'll be tough, but we'll take the learnings. There was a lot of positives, especially how hard we worked. If we add a bit of accuracy then we'll be in a good place to meet the French."
Get ready for a barrage of clichés about still being in the championship and fighting for every point.
But they could give those interviews in their sleep, it’s putting those words into action against a humming French outfit next Sunday that counts.
Follow Ireland v France (kick-off 3pm) on Sunday via our live blog on RTE.ie and the News app or listen live on RTÉ Radio 1's Sunday Sport.
