Could there be a more extreme backdrop to tomorrow's meeting at Murrayfield than the case of the respective out-halves chosen for this must-win showdown? For Ruaridh Jackson, the new kid on the Scottish block, it represents a fourth appearance at this level, but first ever as pivotal playmaker from the start.
By contrast, for the man edging towards the Zimmer Frame in the green out-half shirt, it's Test cap number 106. We won't know whether the 'injection of new blood' or the recall of 'the old dog for the hard road' has had the greater effect until the final blast of Nigel Owens' whistle.
Credit where credit is due to the coaches for having the courage of their convictions to do what is unquestionably the right thing ahead of a match of great significance for both countries. The Grand Slam may already be off the agenda, so too the Triple Crown for Scotland, but given what lies ahead in New Zealand later in the year, it is a pragmatic selection on both counts, based on immediate needs and longer term demands.
I was in Murrayfield and Lansdowne Road for the respective defeats a fortnight ago and I can tell you that disappointing and all though the narrow loss to France was for us, the anger and frustration at the insipid Scottish surrender 24 hours earlier was much more palpable. The Scots were shocking against the Welsh and while we were gallant in defeat against the French so were they in Paris a fortnight before. Confused? So are we.
On the one hand it is the essence of unpredictability, so special to this unique European competition, and on the other it makes all available evidence almost irrelevant come each succeeding round.
In the search for early momentum it is the English and French in that order leading the way. We were poor in victory in Rome, but better in defeat in Dublin. The Scots were, like us, full of adventure (by way of three tries) in France, but lost their way badly in Edinburgh when the Welsh emerged comfortably and without ever leaving third gear.
The Scots were so poor against the Welsh, it was embarrassing, but the message for Ireland is obvious -- beware the backlash. Andy Robinson -- a coach I greatly admire -- has made seven changes to his starting XV. Far from change for change sake, it is major surgery based on evidence and in every area -- including that of the O'Gara equivalent in centurion Chris Patterson -- and smacks clearly of selection with a purpose.
There is a high risk element attached, not least at the heart of the side given an entirely new axis at 8 (Johnnie Beattie), 9 (Mike Blair), 10 (Jackson) and 12 (Sean Lamont). Beattie, like his dad before him, is a big game performer in the same position. Blair and Jackson will pose a greater attacking threat -- the former around the fringes, the latter close to the gain line.
The young Glaswegian out-half is also a better distributor if not quite the same string-puller in terms of kicking out of hand. As for Lamont you can take it as read he will be charging up the 10/12 Irish channel at every opportunity. Short, flat and aimed at sucking in O'Gara in the search for an obvious target and forward momentum. Here David Wallace's role in protecting his Munster mate is obvious. Failure to do so could be catastrophic.
Patterson's presence will, I suspect, remove the burden of goal-kicking from the first time starter at 10. It should help the new out-half adapt with confidence from the off. As for Ireland? Poor in victory in Rome, better in defeat in Dublin, but two weeks on and with what is essentially a settled side (certainly when compared to this Scottish journey into the unknown) the best of both early performances will be expected to deliver our sixth victory in Edinburgh in seven attempts.
There was a time we couldn't buy a win at the home of Scottish rugby (winless there between 1985 and 2003), but that was then, this is now. Add to that the hurt felt following what was supposed to be a Triple Crown send-off to Croke Park in the final game of 2010 and there should be little motivation required tomorrow. Tommy Bowe's re-selection is no reflection on Fergus McFadden whatsoever. The Ospreys' winger is quite simply our most potent attacking force and finishing edge. Once Stephen Ferris was declared unavailable, the pack was re-selected en bloc for the purpose of continuity, not least in the front-row.
At half-back Kidney has acted wisely. I'm not too sure he would have included Eoin Reddan ahead of Tomas O'Leary in the event of both being available, but either way the pairing of Reddan alongside O'Gara will benefit as a unit.
To suggest that the Munster out-half has been selected because of his impact (however good) off the bench against the Italians and French is nonsense and I'm glad the head coach made that clear when declaring in midweek that the purpose was "to keep both guys ticking along."
It is sensitive and sensible selection that does not weaken this Irish side one iota and, as with McFadden, does not reflect in any way poorly on Jonny Sexton's input to date. How could it?
I have been that left-out soldier in my time, so I do know what I am talking about. And you can be sure that Sexton will still do the business when he is called upon. And please, may we be spared this kicking stereotype being unfairly attached to O'Gara. The guy, like Sexton, is a superb distributor off either side.
Two into one may not go all that easily at out-half, but we are blessed with the quality of both options. Unfortunately the same cannot be said at scrum-half where, despite four different alternatives, there is no stand-out individual in the position as of now. That might sound a tad harsh, but it is also the reality. Whether it is Reddan, O'Leary, Peter Stringer or Isaac Boss, we need someone to take control and make the position his own.
For Reddan and Stringer opportunity knocks. We need Reddan to remove that occasional step and concentrate on his sweep, while, from Stringer, we need even the semblance of a breaking threat beyond that faultless pass. Take the best of all four and you've got Colin Patterson. What would we give for that wee man now? Reddan has the bits and pieces. A big one from the Limerick lad tomorrow and we're on our way.
Scotland will be unrecognisable in tempo and intensity from that against the Welsh a fortnight ago. Hopefully, we too will have moved on in terms of discipline and error count. Home advantage favours the Scots, but heart and head working in tandem suggests Ireland to kick on to Cardiff. Ireland by eight.