When the final whistle sounds at the Stade de France tonight, the Irish mood will be determined by cold, hard facts. Not hope or belief or all the other buzzwords that they have spoken of throughout this World Cup campaign.
Tomorrow they will either have everything or nothing to look forward to. Giovanni Trapattoni arrived on a lucrative contract where the stated mission was to take Ireland to South Africa. Whatever happens, there has patently been a progression. But the experiment and the outlay was always about the endgame.
That is why it is so galling for Trapattoni's side to find themselves with the odds so heavily stacked against them. The 70-year-old has pointed out that, after encountering the 2006 champions Italy in the qualifying group, drawing the runners-up in the play-off was a harsh outcome. Ill-feeling lingers over Fifa's goalpost shifting with the seedings draw but the captain Robbie Keane was honest enough yesterday to admit that excuses will provide no solace if they do not turn around a deficit tonight.
The obvious improvements, like the markedly more assured displays on foreign soil, will be rendered obsolete if they are unable to raise that bar in front of a Parisian crowd that is expected to include 15,000 Irish fans.
"The performances away have been good and it's been a decent campaign but it will mean nothing if we don't produce it here," said Keane, "We're in this campaign to be in the World Cup and this game will decide that."
The Dubliner, who turns 30 next July, was honest enough to acknowledge that it could be his last chance to return to the game's biggest stage and he is not alone in a dressing room where the leading players are all in or around his peer group. In that context there is no shortage of desire and, indeed, a healthy degree of confidence.
No team has ever won a World Cup play-off after losing the first leg at home. A global statistic to add to the personal hurdles Ireland have to overcome. Twenty-two years since a meaningful away competitive victory. Eight years without success against a higher ranked side. In short, there is no logical rationale to suggest the visitors can turn this around. Instead, they need something illogical to happen.
"We're professionals," said Keane, "over the years, we've seen strange results happen. There's another twist in this, I believe that."
There were will be no surprises on the teamsheet, though. Trapattoni sticks with the same XI that eventually ran out of steam and fell to Nicolas Anelka's deflected strike at Croke Park which put Les Bleus in the driving seat. Liam Lawrence stays put on the right of midfield, with Aiden McGeady and Stephen Hunt being kept in reserve.
Keane and Kevin Doyle will face a different challenge with Seville centre-half Sébastien Squillaci in line to replace the injured Eric Abidal, which will change the complexion of Domenech's defence.
As Ireland learned on Saturday, however, it is difficult to trouble the opposition if you are unable to get bodies into the box. The dilemma this evening is knowing when it is acceptable to take risks. "I hope that France come out and attack," said Trapattoni. "They cannot stay back and play like they did sometimes in Dublin ... that was a fair tactic because they wanted to achieve the result, but I think they couldn't play the same way at home.
"The good thing about football is that after a disappointment, there is another game. I watched the game from Saturday again and it should have been a draw. We lose, but there is another opportunity on Wednesday." Alas, the statement is irrelevant if Ireland fall short tonight. In that regrettably likely scenario it will be 10 months until their next game of substance. There are few worse places to be playing games of win or bust.