Jim Gavin is facing the biggest challenge of his managerial skills so far as fears grow in Dublin that they have been re-infected by the fade-out virus which caused them serious problems over several years.
It came perilously close to dumping them out of the championship again last Sunday, when Mayo clawed back a seven-point deficit to finish level in the semi-final for a second successive year.
And while Gavin asserted afterwards that the game "will do us a power of good", he must have been as baffled as everyone else as to why Dublin lost their way after Jack McCaffrey's point put them 2-12 to 0-11 ahead after 61 minutes.
It looked as Dublin were poised for an easy win, only to implode on the run-in, failing to score while conceding 1-4 to revitalised opposition.
"We haven't experienced that intensity all season. It was four weeks since our last game and we will be the better team for it (the draw) the next day," said Gavin.
They may well be, but the big question is why they disintegrated so easily in the closing stages last Sunday.
It might have been understandable if the long lay-off left them sluggish in the opening part of the game but that certainly wasn't the case.
In fact, they led by 1-3 to 0-1 after 15 minutes, having risen to the pitch and tempo very quickly and with apparent ease.
However, they were outscored by 0-9 to 0-5 over the next 35 minutes before pressing on against with a 1-3 scoring burst between the 58th and 61st minutes. It looked like the vital break that would finally squeeze the resistance from Mayo.
What happened after that is the big source of concern for Dublin as they rethink their approach for Saturday's game.
Last year's All-Ireland semi-final was Gavin's first real experience of his players losing their grip of a game which had shaped up nicely for them.
They led Donegal by five points after 25 minutes of the All-Ireland semi-final and, with more clinical finishing, could have been 11 points ahead, having missed two good goal chances during a period of near-total dominance against bewildered opposition.
However, that was as good as it got for Dublin. They were hit by a powerful rally, during which Donegal worked through an 11-point turnaround to win the remaining 45 minutes by 3-10 to 0-8. It was a shattering reverse for Dublin, hinting at a return to the fade-out occasions which undermined them frequently in the past.
Last Sunday's failure to repel Mayo late on wasn't anywhere nearly as damaging, since it didn't cost Dublin the game, but it was actually worse in terms of how it came about.
Donegal had 45 minutes to work on a five-point lead last year, whereas Mayo had only 15 minutes (including almost six minutes' stoppage time) to rescue the situation.
They managed it in eight minutes, scoring 1-4 in a period when they made Dublin look like some of the opposition that Gavin's squad demolished so ruthlessly in this year's Leinster Championship.
That easy provincial run, followed by a comfortable in over Fermanagh in the All-Ireland quarter-final, has been raised as a possible reason for Dublin's unease, but there's no obvious logic in that argument since they were leading by seven points past the hour mark.
A more worrying consideration for Dublin is that the inability to protect big leads, which cost them dearly prior to making the All-Ireland breakthrough in 2011, has returned at its destructive worst.
It was a source of deep frustration back then, having almost certainly cost them the Allianz League final against Cork in 2011 and the 2010 All-Ireland semi-final, also against the Leesiders.
Further back, they surrendered a seven-point lead against Mayo in the 2006 All-Ireland semi-final, losing by a point. And a year earlier, they were five points ahead of Tyrone in the All-Ireland quarter-final but were hauled back to level terms in the second half and lost the replay.
There are several other examples too of how Dublin squandered big leads. Kildare won the 2000 Leinster final replay comfortably after trailing by six points at half-time; Derry recovered from a five-point deficit to win the 1993 All-Ireland semi-final.
Dublin led Meath by six and five points in two different games during the famous 1991 Leinster first round saga but eventually lost by a point in a third replay. And two years earlier, Dublin led Cork by 1-4 to 0-0 in the first half of the All-Ireland semi-final, only to lose by four points.
A failure to protect what should be a match-winning lead creates two problems for Dublin.
It leaves them edgy even when they are well ahead while also encouraging opposition to believe that the cause is never lost.