Just as the players had to quickly sharpen their focus following the magnificent win over Portugal, the first batch of the thousands of travellers had to be similarly sure not to overindulge.
Dublin airport in the early hours was packed with green jerseys, traipsing through security checks and making their way towards Gate 418 to board the Aer Lingus direct flight to Budapest, gate closing before the clock had even struck six.
Sombre best describes the mood, but with just a smirk of satisfaction following the previous night's entertainment.
This trip was most likely booked with the greatest of optimism, and as the games progressed, the thoughts of going to visit one of the great European cities to observe a dead rubber was looking more and more likely.
But now, who’d have thunk it?
"In our own hands," exclaimed the Lazurus-like manager Heimir Hallgrimsson, as the reality of beating Portugal started to sink in. Hungary’s victory over Armenia left Ireland hanging by a thread, but this second place position was far from sewn up.
A tale of two cities, Budapest sits proudly along the banks of the Danube.
The Buda hills on the west of the river is mostly residential and recreational, while Pest to the east is home to the city’s commercial centre.
The pre-match press conference and training schedule changed a touch on the eve of the game, allowing just enough time for a 20-minute ramble from hotel to quayside to stand for a while and appreciate the majestic vista.
Rising in the German Black Forest region, the river meanders marvellously throughout eastern Europe, with Vienna, Bratislava and Belgrade among the other cities it passes through en route to the Black Sea.
Buda Castle and many other impressive buildings were visible from the Pest banks, and it really must be a joy of a city to wander throughout the spring and summer months.
But being mid-November, the city has been blanketed by a depressing grey sky with dropping temperatures suggesting the Beast from the East is making a list and checking it twice.
Dark by four in the afternoon, the midday training for the Ireland team needed the floodlights to be turned on to illuminate the pitch properly at the Puskas Arena.
Ferenc Puskas was widely regarded as the greatest player of his generation and one of the sport’s true superstars, leading the Hungary national team, or the Golden Team, as they were known, to the final of the 1954 World Cup, settling for silver after losing 3-2 to Germany in the decider.
Eighty-four goals in 85 appearances for the Mighty Magyars, Puskas would sign for Real Madrid late in his career as a result of the Hungarian Revolution of 1956 and still managed to secure five league titles and three European Cups.
Stephanie Roche, of course, brought the legendary striker back into the Irish mindset in recent years after receiving a nomination for the Puskas Award, the FIFA goal of the season, named in his honour.
So it is no wonder that the national stadium is also dedicated to the great man, and it really is a wonderful arena, a worthy setting for the grand finale of Group F.
Over 67,000 will pack out the stadium on Sunday afternoon and the few thousand Irish will do well to have their songs heard over the vocal home support.
Things being a lot calmer on the eve of the game, as the Ireland manager fulfilled his media duties in the belly of the beast, not wanting to give much away ahead of the big game.
Hallgrimsson, however, had the look of a man in full control of his destiny as he finally saw the fruits of his labour ripen back in Dublin. Is it time to reap the harvest?
Decisions still to be made regarding team selection ahead of the final training session which followed the press conference, but there was certainly an air of optimism emanating from the genial gaffer.
Mineral-rich thermal water simmers beneath Budapest's surface and the city is renowned for its wellness and therapeutic traits.
The wounds of Yerevan may not be completely closed, but perhaps this healing city might prove perfect for the ever-hopeful Hallgrimsson.
Watch Hungary v Republic of Ireland in World Cup qualifying on Sunday from 1.00pm on RTÉ2 and the RTÉ Player. Follow a live blog on the RTÉ News App and on rte.ie/sport. Listen to live commentary on RTÉ Radio 1.
