'We had heart, but not the composure' - deflated fans react to defeat
For 24 minutes in the first half, Irish fans dared to dream. The Aviva lit up when Shane Duffy headed the ball into the Danish net.
But it was then that things fell apart.
It wasn't for a want of trying - or a lack of support.
Thousands of football fans swarmed into the city centre, staying until the bitter end.
Those who couldn't secure a ticket to the match crowded into the streets in anticipation.
There was an air of nervous excitement in Toner's Pub on Baggot Street prior to the match.
Kevin Leech (24), from Killester, was in Copenhagen for the away leg and was hopeful Ireland would create chances.
"I was disappointed that we didn't get an away goal in Copenhagen - it was painful but at least we got another shot at it," he said.
Nearby O'Donoghue's Bar on Merrion Row was also full to capacity with Irish fans.
Jack McKenna (23), who travelled from Belfast, said the nerves were getting the better of him. "I have been really looking forward to tonight and am delighted that I managed to secure a ticket," he said.
The fans packed into Doheny & Nesbitt's bar were on the edge of their seats in the moments before the starting whistle. An eerie silence ensued for a moment, followed by a resounding roar from the fans at kick-off.
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Niall Dunning (32), who has been living in London for the past nine years, came home for the big game. "How could I not be in Dublin for such an important game?" said the Templeogue native.
Diehard Ireland fans Ann Brennan and Janice Butler, from Ranelagh, were devastated they couldn't get tickets for the game. Wearing a vintage 1980s Ireland jersey, Ms Butler said she was happy to see more female supporters in recent years.
"Whenever a group of us go to away games, there are obviously far fewer girls than guys. However, there seems to be a lot more female supporters these days compared to a few years ago.
Las Ravnholt (46) travelled all the way from Denmark to see his country but even he couldn't have predicted the 5-1 scoreline.
"This is my third time in Dublin, so this was a great opportunity to see the match while going to Dublin again.
"I think it's going to be very exciting, but with not many goals scored. The team who will score the first goal is going to win," he said. "The Irish team played very well in Copenhagen, but I think the Danish team have the upper hand."
And the upper hand they had, pocketing four goals and one penalty against a brow-beaten Irish side.
Green-clad supporters could not hide their disappointment as they trudged out of the Aviva Stadium. Although the majority of fans were delighted to see the Boys in Green give it their all, losing the World Cup play-off was a devastating blow.
Wesley McDonagh (23) from Ennis said he gave up all hope when Denmark scored their third goal.
"We had so much hope for this match and the build-up to it was incredible. I really thought we were going to win, but knew we were going to be beaten as the second half progressed," he said. "It was a great atmosphere all the same, but we just didn't get the result."
Louise Carroll, who travelled from Roscommon with her two daughters and partner to see the match, said she was gutted by the loss.
"The first half an hour was the best atmosphere ever but after it just went downhill from there," she said.
"We're now out of the World Cup and have to wait another two years for the Euros."
Cathal Dermondy, from Kilkenny, said 'devastated' doesn't even come close to how he felt last night.
"We just don't have the quality of player that we need," he said.
"Ireland's problem is that we have the heart but not the composure."
However, among all the downcast, disappointed many, Paul Cullen, from Walkinstown, sounded a note of optimism for the future.
"OK, it wasn't a great game for Ireland but the FAI is changing things and doing things differently in fairness for younger players," he said.
"Tonight wasn't great football, but I really think Ireland have a great chance going into the future. The first goal was unbelievable, there was great excitement but it was a big let-down after that.
"It's great all the same to support your country and the loss won't stop me from taking my son to future games."