Ireland's task in this group was never going to be easy, but it's suddenly become almost impossible.
Quite simply, Giovanni Trapattoni's side will have to secure a pretty unprecedented succession of results over their next two games after a defeat to Croatia in Poznan last night that very quickly dampened some of the fanciful talk about replicating Greece of 2004. Now, they look much more likely to copy Greece 2008: out in the first round.
In truth, the inherent flaws in Trapattoni's otherwise efficient system were fatally exposed. A set-up that is completely dependent on defensive solidity produced too many slips. A team that had been warned about playing sides with modern mobility in the middle were completely outmanoeuvred. And, to be fair to Trapattoni, he did not make many excuses.
"They deserved to win because they were superior in midfield," he said. "Our performance was not like previous performances. In many games, we have played better."
Slaven Bilic, the Croatia coach, by contrast, was rather bullish. "I was expecting this kind of result. We were preparing for this victory. We knew everything about this Irish team. We knew we were a better team."
Bilic had promised before this game that his side would alter their usual counter-attacking game in order to get at Ireland. That's exactly what they did. Croatia immediately seized the game as Ireland's pre-match energy seemed to spill over into a rushed anxiety.
By the third minute they had taken the lead. Although Mario Mandzukic first stumbled on the greasy surface as Darijo Srna got his cross over, the forward used it to his advantage to send a well-judged header skipping past Shay Given.
That silenced what had been a raucous Irish crowd and, for a time, seemed to shell-shock the players. In such situations, it's usually only going back to what you do best that calms nerves and rebuilds confidence. To their credit, Ireland did that.
Indeed, they equalised through that template of the Trapattoni era: a set-piece. Sean St Ledger stooped superbly to head home Aiden McGeady's exquisitely delivered free-kick in the 19th minute.
However, instead of seizing the initiative Ireland receded.Over the next 20 minutes, Croatia gradually grew in confidence and cohesion to the point another goal became inevitable. First, Ivan Perisic came inside to go dangerously close with an ambitious – but well-executed – volley. Then, one dangerous piece of passing at the edge of the box required a desperate block from Stephen Ward to prevent a chance.
The next time Croatia got forward, though, Ireland were not so fortunate. Indeed, they were positively unlucky as the ball bounced around the box and came off Ward to the Everton striker Nikica Jelavic, who expertly dinked the ball past Given.
Trapattoni did, however, have a mild rebuke for the Dutch referee Bjorn Kuipers. "I don't know if there was a deflection but the second goal was offside," he said. "Those two goals, we lost it all. The second goal was very important. It kicked us, this moment."
It was the first time Ireland had conceded more than one goal in a competitive game since their last defeat, the3-2 reverse to Russia in October 2010. That was also a match in which they were simply spun out of shape by a more fluid attack.
Moreover, it also at least raises the question over whether a touch more innovation in the formation is needed at this level – as Trapattoni seemed to be leaning towards after the 0-0 draw with Hungary last Monday.
Worse, both of the Croatian goals were inherently scrappy and soft. Here, certain allowances have to be made for the difficulty of the conditions. But, if Ireland are to keep inviting teams on, they simply cannot afford any kind of slip. In that, the formation is inherently hostage to fortune.
Just after half-time, fortune betrayed Ireland again. Mandzukic rose superbly to meet Perisic's cross and, although it bounced off the post, it cruelly rebounded off Given's head and in.
By then, the momentum was completely with Croatia. For the next few minutes they threatened to run riot. Signalling that, the ball was immediately gifted to Mandzukic straight from kick-off and he drove forward in search of a hat-trick.
Ireland could complain of poor luck again when, on 62 minutes, Robbie Keane went down under the challenge of Gordon Schildenfeld in the box only for referee Kuipers to wave the protests away. By then, though, the team were vainly tilting at windmills. Croatia were not particularly impressive at this stage but were largely comfortable.
From there, an Ivan Rakitic effort aside, the game largely petered out. The hope is that a campaign that Ireland have waited so long for will not do the same.
At the end, Trapattoni insisted his players must believe in the system that has got them this far. It does, however, look unlikely to take them any further.
Scorers. Ireland: St Ledger 19. Croatia: Mandzukic 3, Jelavic 43, Given og 48.
Substitutes: Ireland Walters (Doyle 53), Cox (McGeady 54), Long (Keane 74).
Croatia Kranjcar (Jelavic 72), Perisic (Eduardo 89), Dujmovic (Rakitic 90).
Booked: Ireland Andrews. Croatia Modric, Kranjcar.
Man of the match Modric. Match rating 7/10.
Possession: Ireland 45% Croatia 55%.
Attempts on target: Ireland 3 Croatia 5.
Referee B Kuipers (Neth). Attendance 43,200.