The element of glorious unpredictability that can often truly define a championship encroached with startling ramifications when unsung, unheralded Down reduced Monaghan's previously buoyant aspirations of a third Ulster senior football title in five years to debris at a captivated Athletic Grounds, Armagh.
A team that had been fortunate in the extreme to survive in Division Two and to which winning even one meaningful contest for almost two years until January this year had been alien, suddenly, dramatically defied the odds to thrust themselves forcibly into the spotlight at what we like to refer to as the business end of the season - that is, when results can carry massive currency.
Today Down are not just beginning their preparations for a provincial final against raging hot favourites Tyrone on July 16, but they, with considerable justification, are embracing the belief that they have at last ushered in levels of positivity and optimism in relation to the overall health of gaelic football in their county that have been absent for some time.
They did it the hard way, too, in a blood and thunder tie that ebbed and flowed from first whistle to last - a contest that had everything including a change of referee at half-time when Paddy Neilan replaced the injured David Coldrick who assumed the role of linesman.
If this was essentially a triumph honed through a collective spirit, admirable character and palpable pride in the jersey, then it was also a stage on which individual talent flourished, a manager's stoic faith in his charges was at last thunderously acclaimed and the world was transformed into a sporting oyster.
Perhaps, too, the most pertinent aspect of Down's out of the blue coup is that Monaghan, who walloped Eamon Burns's side by 19 points in the quarter-final of last year's Ulster Championship, did not have a bad day at the office on this occasion.
They gave unstinting effort, threw their bodies on the line relentlessly and had their foot firmly on the accelerator even as this enthralling blockbuster sidled into added time.
Down were not to be denied, though.
Darragh O'Hanlon's ice-cool accuracy, Connaire Harrison's five-star display at full-forward, the silken skills of Ryan Johnston, Kevin McKernan's heroics in defence and attack and Conor Maginn's almost superhuman work-rate embossed an overall performance that evoked memories of the early 60s and 90s when the Mourne county was untouchable.
Down's resilience was in evidence in the first 20 minutes during which the superb O'Hanlon converted three frees to complement Harrison's spectacular opening point with Ryan Wylie, Darren Hughes, Jack McCarron and Conor McManus underlining the depth of Monaghan's scoring artillery by posting points. But it was in a lucrative phase between the 22nd and 28th minutes that Down defiantly shed their underdogs status.
Harrison (2), Shay Millar, McKernan and O'Hanlon were all on target before McCarron and McManus knocked over points to keep Monaghan in touch at the break (0-10 to 0-8).
The second-half was just five minutes old when considerable momentum was added to Down's push for victory. Niall Donnelly was fouled in the square by Colin Walshe, the nerveless O'Hanlon stepped up to tuck the resultant penalty past Rory Beggan and suddenly visions of a new era formed.
Yet such visions became clouded when the ubiquitous McManus potted two frees in the 47th and 49th minutes before O'Hanlon seemingly transported Down to comparative safety by spooning his fourth free with only 20 minutes remaining.
Not a bit of it, though. Monaghan showed just why they are among the top half-dozen sides in the country when the McManus-McCarron double act led a concerted blitz that slowly but surely saw Down's significant lead evaporate.
The duo had comprised a hot handful for the Mourne defence throughout and amassed 10 points between them, McManus's consistency from frees always a threat to the opposition.
And when the industrious Kieran Hughes, whose high fielding was a feature of his play, got in the scoring act to leave a point between the sides at 1-13 to 0-15, in the 66th minute we were all mentally preparing for a replay.
But, perhaps in keeping with the occasion, a touch of sporting romance brought the curtain down in spectacular style when substitute Donal O'Hare, who has hardly kicked a ball for his county this year, eased Down to safety with a breakaway point deep in added time.
The Burren ace found himself in splendid isolation as the ball was delivered into him and he made no mistake from close range, his score sending Down fans into unimagined ecstasy as the final whistle loomed
Yes, indeed, it was a match that had everything - truly a contest for the ages.
Down: Cunningham (0-1'45); McParland, G McGovern, O'Hagan; O'Hanlon (1-5, 1-0pen, 0-5f), McGovern, Mooney; K McKernan (0-2), Donnelly;Turley, Maginn (0-1), Millar (0-1); Johnston, Harrison (0-3), Johnston. Subs: O'Hare 0-1 for Harrison(53 mins), Murphy for McGovern (58), McKibbin for Mooney (64), Carr for Turley (65), Poland for Johnston (66). Yellow cards: McParland (3 mins), O'Hagan (31), Harrison (35), J Johnston (44).
Monaghan: R Beggan; Kelly, Wylie, Wylie (0-1); Walshe, Corey, McAdam; Hughes (0-1), Hughes (0-1); O'Connell, Duffy, Duffy (0-1); McCarthy (0-1), McCarron (0-4, 2f), C McManus (0-6, 3f). Subs: R McAnespie for McAdam (42), D Mone for K Duffy (46), Ward for Duffy (46), Malone for McCarthy (56), Forde for Beggan (70).
Referee: Coldrick (Meath), P Neilan (Roscommon).