Eamonn Fitzmaurice described Monaghan as "excellent shapeshifters" and said they had weapons to trouble Dublin, so long as they didn't consider themselves in bonus territory.
Having struggled to find a manager in the off-season, favourites for relegation in spring, and after only finishing third in the group phase, Monaghan find themselves in an All-Ireland semi-final for the first time in five years and only their second in 34 years.
Vinny Corey's side finally overcame Armagh in a gruelling penalty shootout, after a grim arm wrestle of a match, with their legendary inside forward Conor McManus rescuing them by manufacturing and scoring a free in the dying seconds of extra time.
In their last All-Ireland semi-final in 2018, they were narrowly edged out by Tyrone, with many veterans of that effort still around.
While they will be heavy underdogs against Dublin, who rediscovered their blistering 2010s form in Sunday's quarter-final, Fitzmaurice said they have to go in with belief.
"Losing an All-Ireland semi-final is the worst game to lose," the former Kerry boss told the RTÉ GAA podcast.
"There's nothing to take from it. It's just a gut-wrenching disappointment to miss out on the biggest day of the year.
"The likes of Conor McManus, Rory Beggan, Jack McCarron, Karl O'Connell, the Hughes brothers, they've a very experienced cohort, they're going to be saying to the young lads, 'listen, this comes around every five/six years, sometimes longer, for the likes of us, we've a great group, we've a great manager, we've a brilliant coach, we've great spirit, we've good momentum, we've to cash this in when we get here.'
"Traditionally, I found it coming up against them, they are excellent shapeshifters. They're brilliant tactically.
"So many of their players are flexible. Tactically, they can play different roles. They can throw different things at you.
"With Rory Beggan's booming kickout, it gives them another weapon. They have weapons to test Dublin.
"They have beaten Dublin, they've beaten them in league games. They've beaten Dublin even in Croke Park in league games.
"So it's an interesting dynamic. Obviously, with the way the Dubs played yesterday in the second half, if they play like that the next day, there's probably no one that'll live with them.
"But Monaghan, they can't view this as bonus territory, they've to view it as an opportunity."
Ex-Tyrone All-Ireland winner Enda McGinley felt that lack of belief has been an issue for Monaghan this deep into the competition, though he stressed the quality in their current side, saying the traditional narrative about pluck and spirit did them a disservice.
"Coming home, the feelgood one was Monaghan. They're sitting in the All-Ireland minor final, they're sitting now in an All-Ireland semi-final.
"They struggled to get a manager last year. Vinny Corey has stepped up. The job he has done with them...
"It's easy to get into the narrative of it's just this Monaghan spirit, but the quality they're playing with, the younger player and the speed that they have now entering into that team, the tenacity and the honesty they always bring to their performances, I just think it's stunning what they're doing.
"I just hope they get the mentality right. For years I don't think they genuinely believed - and I think it always held them up - that they could win an All-Ireland. Probably different from the other teams that have routinely been in Division 1, who all thought we can win an All-Ireland. I don't think Monaghan genuinely held that belief and that stopped them.
"I did feel, coming into this weekend, when they were playing Armagh that that was their chance, I don't think they would have had a huge fear of Armagh.
"But now they're now playing a team against whom they very likely do have an inferiority complex to. They have to lose that. Because they do have quality. They have more quality than probably they get credit for."
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