There was a widespread assumption in between Hungary's 1-0 win in Yerevan and the kick-off in Dublin on Thursday that Sunday's game could be a dreary dead rubber.
An 'After the Lord Mayor's Show' type affair where dead-man walking Heimir would pitch up for one last engagement in Budapest, do one final testy post-match interview with Tony before hopping on the long-haul flight to Jakarta.
Or best case scenario, they'd need to do an Arsenal '89 and win by two clear goals, perhaps with Chiedozie Ogbene or Mikey Johnston in the Michael Thomas role.
This was not considered a terribly viable proposition given that in recent years Ireland have struggled to beat even lower-ranked nations at all away from home, let alone by two goals.
Then they went and beat Portugal by two goals. The first half on Thursday produced gasps of wonderment far and wide, euphoria mingling with something almost like amusement as everything suddenly fell Ireland's way. Anecdotally, a common refrain from people who weren't watching the first half was that they assumed their score app was playing up when they checked their phone.
Troy Parrott proved himself once again to be Ireland's greatest poster child for leaving the grim toil of the English second tier behind and taking oneself off to the continent.
He was already written off as another lad with a great future behind him during his years slaving away in Milton Keynes and Preston.
He's rediscovered himself out there in the Dutch league, scoring freely first for Excelsior and then for AZ Alkmaar.
Parrott showed glimpses of his Dutch league form in an Irish jersey in an excellent, stylish display in the 2-1 win away to Bulgaria in March. On Thursday, he showed all his new-found zip and confidence, nowhere better than for the second goal, when he expertly steered a shot inside Diogo Costa's near post.
By the time Cristiano Ronaldo was belatedly shown a red card for throwing out an elbow at Dara O'Shea - which felt like a karmic comeuppance for all the times when he seemed to double as the referee's line manager in Portugal-Ireland games - there was a gleeful atmosphere around Lansdowne Road.
In the end, there was curiously little pressure in that seven minutes of injury-time. Caoimhín Kelleher, who developed a slightly alarming habit of slipping on his kickouts in the second half, pulled off one superb reflex save, although we're more or less used to that by now.
Portugal's dainty, genteel, intricate approach is out of fashion these days in the Premier League, where the season's official tagline has been 'Needless to say, Tony Pulis had the last laugh'.
It looked especially toothless against Ireland, even in Lisbon, where the petrified visitors had no notion of attacking. Nathan Collins, Jake O'Brien and Dara O'Shea looked in their element in both games rather than the startled and bewildered rabbits we witnessed in Armenia.
Ronaldo, now 40, is probably of dubious benefit to Portugal at this stage, with his haughty disinterest in the blue-collar business of running around the place and his monomaniacal focus on his own goals tally. The question was raised again in the irate Portuguese press this morning as to whether they'd be better off without him.
Such a debate sparks memories of Ronny's ill-fated nostalgia move to Manchester United in the summer of 2021, where the extent of his culpability in the team's drop from second to sixth place that season was a front in the battle between the tactical eggheads and the longer-in-the-tooth pundits. (The latter could never be got to accept that Ronaldo was the problem when he did nothing only put the ball in the bloody goal the whole time.)
On Ronaldo's last trip to Dublin, he was grabbed in a mid-air chokehold by Shane Duffy, a viral photo almost as popular as the lads eating their lunch on the crane in New York.
Now, suddenly, it looks like Heimir is the man most likely to lead Ireland into Euro 2028, regardless of what transpires in Budapest.
Even Eamon Dunphy is writing articles announcing that he "owes the Dentist an apology".
His short but eventful reign has followed a strange pattern, where, just at the moment when things appear at their most hopeless, Ireland pull a result. The win in Helsinki last year is hardly comparable to this scalp but was badly wanted at the time and was preceded by an even greater level of despondency.
Ronaldo's conspiratorial assertion that the Ireland manager had gotten him sent off won't have done the latter much harm either.
The pride and giddiness in the wake of the landmark victory has easily swallowed any pangs of frustration people might be feeling about the mis-steps earlier in the group, which has left Ireland still clear underdogs to get into the play-off spot.
Ireland have their history with Hungary. The most famous meetings were at the end of the 1980s, when the Hungarians were in precipitous decline while the Boys in Green were making a rapid ascension. European championship regulars, the hosts have remarkably not reached a World Cup since 1986.
Viktor Orban's government has pumped millions into football clubs and academies, making the Irish government's very welcome commitment of €3 million per annum to LOI academies look fairly small-scale by comparison.
Orban would likely take an exceptionally dim view of Hungary's footballing sons missing out on yet another World Cup by virtue of losing a decisive home game to Ireland. One could easily imagine him giving their Italian gaffer the thumbs down in the fashion of Jaoquin Pheonix in Gladiator in the aftermath of a defeat.
For the night that was in it, after so many years of dispiriting results, people were content to celebrate Thursday's win simply for what it was, rather than fretting about the permutations or pondering any what-might-have-beens.
And it means that Ireland will take the group to the last game. After the last half-decade, that represents definite progress. And the manner in which it was done has convinced many that anything is suddenly possible as they head for the Hungarian capital.
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
