Despite being considered a significant second fiddle to Spain and Italy's cagey, engaging midday draw, we should have seen this coming. Group C was already pressurized given the four teams pitted against one another, yet that pressure increased thanks to the 1-1 result in Gdansk between the presumptive favorites to advance. (That, plus the tension accompanying overnight reports of fighting between fans that resulted in 14 arrested.)
And so, for a breezy 90-plus minutes, Croatia and Ireland pleasingly shed any notions of grim, functional soccer in search of a leg up in the bid for a quarterfinal berth.
That the score line fell heavily in Croatia's favor -- 3-1 the final result, with a brace from Mario Mandzukic (with Shay Given assist) bookending a predatory Nikica Jelavic strike -- was merely a footnote to yet another paradigm shift at Euro 2012. All the sides we expected to underwhelm thus far -- Ireland, Croatia, Greece and Russia to name but four -- have been pleasingly expansive. Arguably the least enticing game thus far involved high-octane Germany and a Portugal side blessed with Cristiano Ronaldo's abundant gifts.
But back to Group C's late game. In Poznan, Ireland's settled, EPL-seasoned back four (long thought to be its greatest asset) was rattled time and again by Croatia's 4-1-3-2 formation that made the most of its wealth of attacking talent. Mandzukic and Jelavic's continual motion in the final third opened up gaps for Luka Modric and Ivan Rakitic to exploit either on the run or in the pass.
The Croats did get lucky in the early going. Barely three minutes in, a deflected cross fell to a wrong-footed Mandzukic, hanging in the air just long enough for the VfL Wolfsburg striker to regain his balance and direct a header to Shay Given's near post. Agonizingly, the Aston Villa goalie couldn't spring back across his line and prevent the early goal.
Yet Giovanni Trapattoni's side didn't appear too rattled. Oft-mocked for a cautious approach, the Irish created several opportunities to level: Damien Duff whiffed on Kevin Doyle's knockdown and failed to trouble Stipe Pletikosa. Steven Ward's 10th-minute cross caused panic before being cleared. Then, on 18 minutes, a free kick from the left flank -- won by Doyle as Vedran Corluka came clattering in -- was swung to the far post where defender Sean St. Ledger outleapt Corluka and nodded home.
Just reward for an aggressive fight back, but it proved to be nowhere near enough as the Croats simply turned up the tempo. Both Ivan Perisic and Modric drew fine reactions from Given midway through the first half before another fortuitous bounce gave them a deserved lead. After the Irish rear guard failed to clear a corner, the ball pinged to Jelavic and he smartly chipped the ball over an onrushing Given with three minutes left in the half. Though Jelavic was in an offside position when the ball skidded onto his right foot, the flag stayed down due to it being passed off an Irish foot. Poor luck, but the Irish played for a whistle that never came, a cardinal sin in any sport.
Minutes after the interval, more gloom for Trapattoni (who had an uncharacteristically poor game) as Mandzukic capped a flowing Croatia move with a header off the post that caromed off the back of Given's head and in for goal No. 3. The cross was inch-perfect and Jelavic cleverly screened St. Ledger, giving his teammate room to direct the ball goalward.
From there, the Irish fought gamely -- Keith Andrews put a close-range header right at Pletikosa, then sent another effort wide in injury time -- but couldn't force a nervy conclusion, giving Croatia a comfortable and deserved win. Though all three of its goals carried a modicum of luck, the slick build-up play and confidence of Croatia's front five merited such fortune.
Bilic nailed his formation and his team selection; not only did it play up to Croatia's attacking strength, but the choice to maintain an attacking bent ensured that the Irish would be too preoccupied at the back to trouble Croatia's nervy and ill-equipped defensive unit. Vedran Corluka was a liability at center back. Gordon Schildenfeld was far from assured alongside the exiled Tottenham defender and will be tested against more mobile strikers than Ireland's duo of Doyle and Robbie Keane.
But these are problems for another day. The 3-1 win not only consigns the Irish to a tournament on the periphery but reinforces that the Croats are back to the pedigree of Euro 2008 from the team that missed out on the 2010 World Cup.
Spain and Italy should be concerned. The Croats will push them both hard for a spot in the quarterfinals.
Man of the Match: Mario Mandzukic. Worked tirelessly all over the field for the cause and made ample use of his 6-foot-1 frame to rattle the Irish defense. Though lucky on his second goal, full value for his brace. His aerial dominance in particular created plenty of opportunities for Croatia's front five. Bilic will hope that his late injury isn't serious.
Final verdict for Ireland: The road back is virtually insurmountable. Would need to conjure up the magic of U.S. '94 to defeat Italy, though a loss to Spain in the meantime would render such heroism moot. The luck that got them here appears to have run out.
Final verdict for Croatia: In control of Group C thanks to Spain and Italy's inability to force a result. But Bilic must devise a way to patch up his defense in advance of facing Antonio Cassano & Co. on Thursday.
Talking point: Did Robbie Keane deserve a penalty midway through the second half when clipped from behind by Gordon Schildenfeld? Probably. The call could have revived Irish hopes at 3-1 down, but don't let it overshadow a disappointing afternoon around goal.
James Tyler is an assistant editor for ESPN.com’s soccer coverage.