For the first time in this Championship Joe Schmidt has some serious decisions to make.
If it's true what they say about teams learning more in defeat than victory - and I'm sceptical on that one - then the master of improvisation and reconstruction will have a plan for Edinburgh that embraces measured change.
Root and branch surgery will not be required. With a seven-day turnaround, it won't happen anyway but in balancing the needs of a Championship still there to be won (even if it's no longer in our own hands) against a World Cup fast approaching, there is a call to be made .
Does Schmidt leave well enough alone on the basis of one blip in four - or does he measure the inadequacies in Cardiff and factor in changes that will give game time under pressure (and that part is key) to other players in what is undoubtedly an ever-extending squad?
A case could be made for seven, possibly eight, changes post-Cardiff. Apart from an extraordinary performance from the skipper Paul O'Connell, not too many in green came away with their reputations enhanced. But on the basis that a developing team didn't become great on the back of beating the English and French (and that is some achievement), equally that same still-developing team hasn't become a bad one following defeat to Wales.
We just didn't play well in Cardiff. We started slowly, we lost the battle in the air, we struggled at the lineout yet dominated possession and territory in almost two-to-one in percentages.
Therein lies the problem. We lack the wherewithal of the top rugby nations, chiefly the southern hemisphere three, of being able to turn possession into points and meaningful line-breaks into tries.
The French still have it in their DNA; the English under Stuart Lancaster too and the Welsh, even on limited opportunities, are still ahead of us at this point in time. It is a major concern and Joe knows it.
The new centre combination has bridged the Brian O'Driscoll-Gordon D'Arcy void much more pragmatically than any of us would have expected. Robbie Henshaw and Jared Payne are two very talented footballers well capable of performing at this level but as an attacking combination they have much to prove.
Henshaw is a natural and here to stay, whether wearing 12 or 13. With Payne the case for outside centre is still unproven. When he plays in the last line for Ulster, I see a much more efficient and much more effective Ulster team.
But what is the alternative? With a short turn-around to face the Scots at Murrayfield, time just doesn't allow an alteration in the middle. Luke Fitzgerald has been playing there for Leinster and doing a good learning job but I suspect his immediate future at the highest level will be challenging Simon Zebo for the wing position.
At the very least Fitzgerald should be on the bench as Felix Jones, for all his bread-and-butter quality, is not the utility three-quarter to whom you look for impact in a crisis.
To see Fitzgerald warming up with the squad prior to kick-off and then having no role to play is one area that I disagree with the head coach. I've heard some arguments put forward about not wanting three left-footed players in the team at the same time (via mid-match substitution) as in Rob Kearney, Zebo and Fitzgerald. I hope that's not true as it is taking performance analysis to ridiculous extremes.
So on the basis of picking a team to challenge for the championship yet still build meaningfully towards Webb Ellis 2015, what changes could or should the main man make for Murrayfield?
He could, for starters, throw in the replacement front-row en bloc but here he must measure the 80 minutes by way of all six. Rory Best and Mike Ross, with respect to two very seasoned performers, are long past replacement impact.
Sean Cronin is worth a run from the start as is Marty Moore but in the search for balance plus game time, I would give Cian Healy the nod, not because Jack McGrath did anything wrong but for the simple reason that Healy needs it more.
In the second-row, the same could be said for Devin Toner ahead of Iain Henderson but Henderson is now demanding selection from the start. The experience of preparing for a game of this intensity alongside Paul O'Connell would do him the world of good.
I suspect it will be Toner but here I would go with my gut and start Henderson. A strong case can also be made for having Rhys Ruddock as a back-five reserve.
Beyond that, I would leave Conor Murray in situ despite another Eoin Reddan tour de force after his arrival on 60 minutes the last day which really upped Ireland's tempo.
And if Johnny Sexton is carrying any sort of 'twinge' then the case for rest in Edinburgh is obvious. Ian Madigan, despite minimal game time in the out-half position this season, was outstanding in his lone start against Georgia for Ireland back in November.
We'll leave it to the medics to decide but Madigan at ten with Ian Keatley in reserve would represent practical thinking for me.
I would leave the midfield combination in place, although I would like to see Madigan at 12 with Henshaw wearing 13 at some stage during the summer. So on the basis of minimal time between matches and a Six Nations title still on the line in Edinburgh, plus rest for Sexton, my starting team to face Scotland sees just three changes.
Despite the disappointing result, Saturday's game in Cardiff, well the second half anyway, provided the most gripping spectacle in the 2015 Six Nations to date. You could cut the atmosphere and tension in the Millennium in that second 40 with a knife.
Entertaining rugby is not Barbarian rugby and never but never would I argue a case for that. However, what we witnessed in the Principality was rugby from the heart from two hugely committed sides in search of the same result.
As long as we have that there is hope but equally let it not blind us to a game in which tries at the highest level are becoming as rare as hens' teeth.
My most optimistic friends tell me these things work in cycles and that attack-minded coaches will again have their day. I dearly hope they are right and I will continue to write passionately and positively on a game I love.
However I still harbour grave concerns when the post-match stats recording Irish domination show three line-breaks (two by Paul O'Connell) and one penalty try at the end of an enthralling second half. We live in hope. Roll on Murrayfield.