Bosnia's fear of failure boosts O'Neill
But big game at Aviva overshadowed by concerns about Euro 2016 in France
Professional footballers rarely allow their minds to wander into the real world when dark and incomprehensible deeds are being done but this time is very different.
They can't afford to. Society gifts them temporary release from important affairs which in turn, allows us to pretend, for 90 minutes at least, that the only thing that counts is happening on a patch of grass in front of us.
It also allowed Martin O'Neill and Ciaran Clark to sit for the pre-match media briefing before a definitive Euro 2016 qualifying game and behave as if nothing was more real than Bosnia and Edin Dzeko's talent for sniffing out goals.
They must remain stubbornly in their fantasy world and do their job because if they do not, we are all lost.
Up until Friday night, our hearts desire was to be in France next summer and experience to the fullest all that a major finals offers in a country where the joy of life is celebrated better than in most other places in the world.
But no matter how excited we might be about the possibility created by Robbie Brady's fog- shrouded goal in Zenica, there is now a hard knot of apprehension; a sense that lunatics with warped brains could be waiting around any corner with evil intent.
They tried to implement their sick strategy in the Stade de France and let it be known that all bets are off.
What was previously neutral territory, a sanctuary of sorts, has been singled out for attention and while it would be crass to suggest that there is anything different about being slaughtered in the street or at a gig, to attack a stadium was definitely something new.
Of course there have been occasions in the past when football venues were caught in the crossfire but this was a premeditated targeting of a full stadium and with the clear intent of removing an almost universal taboo against such an act and destabilising the environment around next year's Euro 2016 finals.
It is a bizarre context for tonight's game in the Aviva and a very frightening one. After a spending a few days in Sarajevo, a city which is still walking a tightrope after a brutal civil war and seeing the bullet holes in the buildings, the graveyards and hearing tales of sniper alley and appalling savagery, events in Paris seem all the more real.
We had our own torture for 40 years and have no high ground to stand on here but even at the height of the troubles, we were able (just) to drive into a rabidly hostile Windsor Park and drive back out again in one piece, if not in peace.
Bosnia's suffering is still fresh in the minds of Mehmed Bazdarevic and his players it is very obvious that the national team has become a symbol of unity, a rallying point.
And because football is separate and supposed to stand above the extremes which lead to conflict, we are allowed to wish for the worst for Bazdarevic in the Aviva Stadium tonight without wishing any ill on kind and friendly Bosnian people who were delighted to see us in Sarajevo.
Fear played a big part in Bosnia's performance in Zenica. We were lead to believe that Ireland would face a deeply hostile atmosphere but that was an over-egged notion. Raucous and maybe rowdy but largely good-natured.
If anyone showed fear it was the Bosnian players and perhaps there should be no real surprise about that. For obvious reasons, play-offs for big tournaments are not something they've ever had to deal with before and we've been in more than our fair share.
Our most recent play-off experience was as good as it gets against Estonia. The one before that was another story.
It was odd to watch Robbie Keane stretching his legs with the non-playing substitutes in Zenica in the murk after the game. He's been in a few.
As much they can be, his legs will be fresh and it was difficult to suppress the thought that maybe he could yet have the decisive intervention in this wild and woolly progress towards France. If Ireland need a penalty taker, he'll be there.
Jon Walters will be restored to the Ireland team, which will require some alterations up the pitch and if John O'Shea puts his hand up when O'Neill asks for volunteers, he will have a big choice to make in defence as well.
Daryl Murphy was rested yesterday after a kick in the calf in Zenica and the logical route for O'Neill would be to pick the same team with Walters starting as the lone striker, supported by Wes Hoolahan. Any input from Shane Long will come late and would be a bonus.
Nobody would envy O'Neill's task if he had to tell either Richard Keogh or Ciaran Clark to step aside for O'Shea and there is a good argument to leave that partnership, with very recent hands on experience of the challenge presented by Dzeko, in situ even if the Sunderland man is fully fit.
O'Neill knows that his defence was able to contain Bosnia with some ease and that must be a great comfort to him given the need for Ireland to behave like the home team and try to press the advantage an away goal gives while avoiding the sucker punch.
For the first time, there is the sense that Ireland can actually make it to France and that will be reflected in a full house and massive support from the stands for O'Neill and his team.
But it will be an occasion tempered with deep sadness and by the knowledge that there are more important things than football as we look towards next summer with anxiety and concern.