Within minutes of Scotland being drawn to face the Republic of Ireland it it was being described as "the fairytale return" of Martin O'Neill to Parkhead.

"I would relish taking the team to Celtic Park," said O'Neill himself. Going back nine years after he left as manager would be "terrific". As soon as those words were uttered there was a compelling case for staging the game at Ibrox.

There is warmth between Scotland and Ireland as countries. When the Irish qualify for tournaments most Scots want them to do well (presumably they would reciprocate that goodwill, although since France 98 we've never tested them with the opportunity). The relationship between the men who will clash in this monumental Euro 2016 qualifier on Friday is not just cordial in a vague sense, it is personal.

Steven Naismith, Aiden McGeady, James McCarthy and Seamus Coleman are team-mates at club level. McCarthy and James McArthur have been close friends ever since their teenage emergence at Hamilton Academical. They even won an FA Cup together with Wigan Athletic.

Steven Fletcher and John O'Shea are team-mates. Shaun Maloney and James McClean are team-mates. For heaven's sake, Strachan was talking in today's papers about sharing a bed with his mate O'Neill during the World Cup in Brazil, like Morecambe & Wise. We'll do well to get the game started at all with all the high-fives and blethering that'll be going on before kick-off.

But given all of these saccharine elements it has been encouraging to sense a hardening of the tone from within the Scotland camp. Yes, O'Neill will have the pleasure of returning to the stadium where he ruled for five years, but the old place won't have the crowd and the atmosphere he knows. To the SFA's credit they took the decision long ago that they would play hardball over the allocation of tickets and allow the Irish the bare minimum, just 3,209. Doubtless the FAI will reciprocate and give Scotland only the mandatory five per cent of tickets for the return match in Dublin next June. That will be a price worth paying. Taking as many tickets as possible, in the country's largest football venue, amounts to a declaration of intent.

And then there was Strachan's blunt, comically non-PC stance on whether the support should go easy on McGeady and McCarthy, who upset plenty (and infuriated a few) by choosing Ireland despite being born and raised in Scotland. "No. They can do what they want," said Strachan of the punters. "Are you going to ask them to pay 60 quid and then they cannae say something?"

Those who equate McGeady and McCarthy to the numerous English-born players who have appeared for Scotland miss the point, perhaps deliberately. No Scottish fans bothered about Ray Houghton, Owen Coyle or Tommy Coyne playing for the Republic because they were unwanted by the Scotland managers of the time.

Similarly James Morrison, Russell Martin, Chris Martin and all the others are only with us after accepting that they were never going to get a look-in with England. The issue here is simple (and non-sectarian): it's football fans feeling snubbed or betrayed by great players who go elsewhere. If England had a Scots-born player he'd get it far worse than McGeady or McCarthy in the friendly that comes four days after the qualifier.

That is the essence of the hostility towards the two Irish players but more column inches have been devoted to the matter than it deserves. Booing of the pair of them isn't likely to be especially noticeable beyond the opening minutes. After that their touches will be lost amid the general melee of the biggest fixture Scotland have played since Italy were here in 2007.

It is a devilishly difficult game to call. These are two teams who draw their men from Everton and Sunderland and Stoke and Wigan, from Millwall and Cardiff and Hull and Blackburn. Strachan and O'Neill fish for players in the same pool (although the superb McCarthy, who is a slight doubt for the game having suffered a hamstring twinge today, was being linked with AC Milan over the weekend).

They are unfashionable clubs who graft and battle and scrap. Scotland are building a system based on width, quick counter-attacking and understanding and movement between their front players. There is a bit of style and even sophistication about it when it comes off. Yet Strachan has acknowledged Friday will be a "cup tie", a "derby" and a "British-style" battle.

Scotland have yet to deliver a big result in Group D. Drawing in Poland was good, but Ireland drawing in Germany was big. They had three chances to Germany's 18 but snatched a 94th-minute equaliser. Eamon Dunphy, Johnny Giles and Liam Brady, the national network RTE's celebrated pundits, were unimpressed by how they went about it. Giles said Scotland had shown far more in Germany the previous month despite losing 2-1.

"Scotland aren't considered to have much better players than us. But it didn't look to me like they thought 'well, we're playing away from home, so we've got to play in a certain way'. So if you're looking at the long term I think Poland and Scotland, at the moment, are ahead of us."

RTE's panelists aren't particularly popular with Ireland's management and players. They couldn't care less. They do what they think is necessary to get the job done. That's a lesson for Scotland ahead of this monumental, crossroads fixture.