What, I wonder, was the absolute pinnacle of his playing career: Northern Ireland beating Spain in the World Cup finals or Nottingham Forest lifting two European Cups?

Ireland’s manager puffs out his cheeks before reeling in the years.

“At club level, if you had said to me as a kid growing up, that I’d be involved in European Cups, I’d have been thinking of Puskas, Di Stefano, George Best,” he says. “So for us at Nottingham Forest, a provincial side, for us to do it was just phenomenal. They’re the magical moments, ‘79 and ’80. And then a couple of years later to cap it at international level, to play for and captain Northern Ireland at a World Cup and to win in Spain…”

He puffs out his cheeks again.

“It’s hard,” he smiles. “Maybe later on in life I might think one might have gained more importance than the other. But at the moment it would be hard to choose.”

One distinction O’Neill is prepared to accept between triumph for club and country, however, is that the latter can exert a more profound social impact, a phenomenon he experienced at first-hand when Northern Ireland enjoyed those unforgettable hours in the sun in Spain in 1982.

“Absolutely,” he says. “At the time, of course, there was still a lot of trouble in the North. And I thought that, at least for a little while, it seemed to galvanise the country. Galvanise might be the wrong word but it seemed to bring people together for a while. I think actually, if I want to be honest about it, I think Barry McGuigan would have done that more so than anyone when he was fighting and there was a very temporary unification of the country for a while.

“But there was always a good feeling [in the Northern Ireland team] with both Protestants and Catholics playing in the side together and players had a great feeling for each other. And there was also a kind of special feeling about being involved in Spain at the time. We knew for us, Northern Ireland, it might not come around too often again so [the attitude was] go and enjoy it as much as you can. And the further we went into the competition, of course, the more euphoric it got.”

Now that he has made the move into international management, football’s perennial club v country debate is once more a live issue for Martin O’Neill.

From early in his tenure he has spoken about the practical adjustments involved, most notably having to trade the day to day involvement on the training pitch at club level for the limited time he gets to spend with the Irish players.

But though he must now find himself viewing the international calendar from a different perspective — especially where friendlies are concerned — O’Neill plays down the extent to which he is a gamekeeper turned poacher.

“Even as a club manager I used to put myself into the international manager’s position,” he reveals. “Of course, the last thing you want is to be sending a host of your players away and then finding half of them get injured. But then I used to think, ‘what would the international manager be thinking — this is his opportunity to get the players, he has to be selfish about it’.

“I had thought about it from both sides so, from that viewpoint, turning the table around the other way wasn’t that difficult.”

Yet the club v country debate is also an increasingly philosophical one, with Arsene Wenger hardly alone but certainly among the most vocal in arguing that the Champions League is now the benchmark for excellence in the game. Again, O’Neill, given his own experience of football across the very highest levels, is well-placed to offer an informed view.

“Club managers like Arsene Wenger are obviously going to think it’s the pinnacle, which it is at club level,” he observes. “You’re aiming all the time to qualify. But it would be interesting to look at the teams that eventually make the last eight in the last number of years. Is there a common denominator? Is it the same sides? There are a number of teams in the Champions League, that I have seen, that would get knocked out relatively early in the Europa League, believe it or not.

“Not every side playing Champions League football is the quintessence of excellence. Absolutely not. But that doesn’t mean it’s not a great competition. Of course it is, it’s a really fantastic competition. And when you reach the knockout stages it becomes really big.

“So, right, I can understand club managers thinking, ‘this is it’. You always hear the phrase coming up that to attract the best players you have to be playing or at least vying for Champions League football. I think there’s a great deal in that. The Champions League has become the Holy Grail of club football but by the same token the World Cup and European Championships have become the majors for international football.”

So he doesn’t agree with those who believe that the international game has been diminished by the rise and rise of the Champions League? “No, I don’t think it has. Because international football is now given its own time, they’re actually taking lumps out of the season, whereas years and years before you played your qualifying games thrown in on Wednesday and you were back for the Saturday. I don’t think, until you actually qualify for a competition — like Northern Ireland did for the World Cup — I don’t think people actually remember how you qualified. But I think the international games, because of the number of weeks handed over to it — interrupting club football in many aspects — has its share of prominence.”

Unfortunately for O’Neill in his current role, the Champions League is something of an abstract concern in so far as Irish involvement in club football’s elite competition is conspicuous by its absence. I ask him if he thinks experience of Champions League football can help a player in the transition to the international game.

“I think you would like, if at all possible, for the majority of your players to be playing major football, big, big football,” he says, “but not everybody can play in the Champions League. Or if you were choosing from the Premier League it would be great. But in relation to ourselves, or Northern Ireland for instance, it will always be the way that you won’t have a squad of 23 players — unless you’re unbelievably lucky at the time — all playing in the Premier League. And you won’t have that many players playing Champions League. With a little bit of luck for one or two younger players, hopefully it will happen.

“Will it prepare you better? I think the more big occasion games you play, I think the less intimidating grounds and venues and opposition can be to you. I felt that anyway with Nottingham Forest when I was a player. Once I started playing not only in the big league, but actually winning big matches and going into the European football, then I felt that probably helped me when I was playing for Northern Ireland.”

As a manager too, O’Neill reckons that some of the experience he banked leading Celtic into Europe can be applied to Ireland’s place in the international scheme of things.

“I think you can draw on those things absolutely. Certainly in the latter stages of the Champions League for a start, but then when we had the Uefa Cup run there wouldn’t have been too many matches, I would say from the last 32 inwards, that we wouldn’t have been second favourites in the game, particularly the Liverpool match and you could think of Stuttgart as well. But isn’t that part of the achievement or the determination — call it what you want — just to go and compete against sides that you might think on paper might have the upper hand on you?”

That, he emphasises, is a big part of the job satisfaction for a manager.

“Absolutely, of course. You know what, I think that will always remain, the side trying to draw on everything to win a game that, on paper, you’re not favourites to win.”

With Uefa’s ‘Nations League’ concept only adding to the debate, one criticism of the international game — which finds pockets of support within both national and club football — is that the existing qualifying process for tournaments has become too unwieldy. Former Liverpool midfielder Didi Hamann succinctly expressed the gripe on a recent visit to Dublin when he wondered aloud what point there really is to Germany having to play Gibraltar in Ireland’s Euro 2016 group.

“Well, again, you started the conversation looking at it from two different angles, at club and international level, and I think I can look at it from this viewpoint,” O’Neill reflects. “You know, if you were involved with Germany, Spain and let’s say England, teams you know are going to qualify all of the time, then I’m quite sure you might think there’s a botheration attached to that part of it. But if you’re involved with that supposed botheration, I think you would look at it a wee bit differently.

“I’ve seen this in England, way back. Do you remember Leeds United once got knocked out by Colchester United [3-2 in the fifth round of the FA Cup in 1971] and they said they shouldn’t even be in the FA Cup. Sorry, they are in it and it may be a botheration to you because they might upset you and they might embarrass you but, sorry, they’re part of it.

“It’s a wee bit like when Ireland’s cricket team beat England [in the 2011 World Cup] and then they were talking about taking these teams out of it. And there was a bit of an outcry. Not that I want to start comparing us to the cricket team. But, at the end of it, there are two different ways of looking at it, and if you are one of us — and I think there are more of us than there are the major sides — then I think you would look at it in a different way to a German, like Didi Hamann.”

So he sees nothing wrong with having a bit of the romance of the cup in international football? “Why not? Why not? Really, if I did look at it from, let’s say, a German or a Spanish viewpoint, I still think I’d feel the same as I do now as an international manager of the Republic or anyone else of that ilk. I think I would feel the same. ‘Yeah, okay, that’s part of the whole thing, we might — if we don’t play brilliantly on the day — be embarrassed a little bit’. But I think you deal with that because you’d expect to get through.”

Indeed, the obvious thought strikes that it will be Ireland cast as the superpower when it comes to playing European football neophytes Gibraltar in the Euro qualifiers.

“That’s a good comparison to make, looking at it from a Gibraltar point of view,” he enthuses. “They’re in the group, they’re new to proceedings and I’m sure they’re delighted to be in it. I don’t honestly think that the teams that are involved will consider that a botheration.”

And then Martin O’Neill pauses and adds with a smile: “Maybe if we get turned over or don’t beat them then I’ll have a different viewpoint.”