O'Neill is adamant he will not risk a player who is a key member of his strongest team unless he is convinced he is fully fit ahead of Thursday night's game at the Aviva Stadium with a trip to Moldova to follow three days later.

He said: "I've been involved in club management for quite some considerable time, less so as an international manager. I have never played anyone who has arrived and not been properly fit, against their will to play.

"That has never been the case and, in fact, as an international manager, I've been pretty lenient about those particular things."

O'Neill has seen McCarthy step up training since his arrival in Dublin and will make further checks on Thursday morning before making a final decision.

He said: "I would listen to the player, and the player has come over here and trained. He hasn't played for a couple of weeks.

"Would fitness be a concern? Of course. Lasting the match would be a concern. But if the injury has cleared up, I wouldn't see that as a problem."

The Republic needed a late Daryl Murphy equaliser in Belgrade to secure a 2-2 draw with Serbia, and know there will be little margin for error in this double-header if they want to make it to the finals in Russia.

They took six points from Georgia during the last campaign, but played two closely-fought encounters and O'Neill is expecting much the same again.

O'Neill said: "Anyone who watched the matches over the last couple of years will know it's a difficult game. Georgia will take points from teams, without doubt.

"Every result is important, every game is important and we have got to be ready. We have never been in a position to treat any team lightly, and we certainly won't treat Georgia like that because they have got some excellent players."

The Georgians, ranked 137th by FIFA, also have an experienced coach in Slovakian Vladimir Weiss, who guided his native country to their first ever major tournament finals at the 2010 World Cup in South Africa.

But O'Neill, who took 31st-placed Ireland to Euro 2016 in France this summer, insists it will be the players and not the managers who will ultimately make the difference.

Sitting alongside captain Seamus Coleman, the 64-year-old said: "I'm not inexperienced myself, you know. If you ask me have I enjoyed international management, yes I have and one of the main reasons I have enjoyed it is because we have qualified.

"We qualified for France and we had some really great performances out there, including beating Italy. But I don't look at it like that.

"The most important thing is sometimes forgotten in this day and age: the game is about players and that has to be recognised sometime again.

"You are asking about enjoyment and I have had a really excellent career as a player and a manager. I have enjoyed it. Which have I enjoyed most? Playing.

"Seamus might be at some stage or another taking his coaching badges - I hope he takes them when he's 49 and plays as long as he can because playing is the best thing you can do, honestly, it really is. This is second-best by a good way."