Mayo were 10 points to the good on Sunday early in the second half, leading 0-17 to 0-7, and yet they were reduced to stumbling over the finish line to win by three.
Had David Clarke not made a tremendous save in a one-on-one with Bernard Brogan near the finish, which would have levelled the game, it would probably be Dublin who would be facing Donegal in the All-Ireland final.
Normally it is mistakes inside the white-wash which costs teams in big games, but last weekend the Dublin management team made some incredible errors of judgment.
They finished the game with a more balanced, more mobile, and more potent team than the one with which they started.
Firstly, Michael Darragh Macauley, who is an all-star midfielder, should have been selected in that position to the exclusion of either Denis Bastick or Eamon Fennell with Eoghan O'Gara as an inside forward alongside Bernard Brogan.
And how a clearly unfit Alan Brogan was brought on at half time is beyond comprehension. The man was obviously not right, and how he saw action ahead of O' Gara or Kevin McMananon, who shot 1-3 when he last started a full game for Dublin, was a key factor in Dublin's defeat.
A player will nearly always feel he is in better shape than he actually is, and most players will "chance it" to see some action.
However from the first ball that he fumbled and when he could not chase after Keith Higgins, it was clear that Pat Gilroy had burned up two substitute slips to no avail.
When Dublin finally got their team set up as it should have been far earlier, they hit Mayo for eight points in a row and cut a 10 point deficit to two.
They had all the momentum at that juncture and it was left to young Cillian O' Connor with his seventh point from a high pressure free to finally stop the rot. O'Connor, who was young player of the year, showed real character when he slotted over two early 45s to give Mayo a foothold in the game. He is a very fine young footballer.
Credit to James Horan's men, too, for hitting three mini-scoring patches that won the game for them.
They hit 0-5 on the trot early in the first half, 0-4 just before half time, and the purple patch at the start of the second half when they scored five points without reply is what won them the match. The likes of Alan Dillon and Kevin McLoughlin and Aiden O' Shea were superb for Mayo at those key times and all played incredibly well.
It was only when Dublin repositioned Macauley to midfield, brought on O'Gara and McManamon, and put Diarmuid Connolly to wing-forward that they inched their way back into the game and they had the run on Mayo in the fourth quarter. However, the home side had left their gallop too late, and left themselves with too much to do.
Mayo's substitutes, and their fresh legs in the shape of Seamus O' Shea, who hit a great point, and Jason Gibbons, who won a vital kick-out, helped steady the ship. Had the Connacht champions been defeated last Sunday after leading by 10 points, it would have been an exceptionally cruel blow to their psyche.
This group of Mayo players now have the task of making sure they do not lose another All-Ireland final after their heart wrenching defeats in 1989, 1996, 1997, 2004 and 2006. One consolation is at least they will not be facing their nemesis Kerry in three weeks’ time.
Having been in Croke Park for Donegal's two wins over Cork and Kerry and then last weekend's victory for Mayo over Dublin, it is impossible not to say that Donegal looked the superior team.
They just looked a more complete team than Mayo do at present.
However that kind of talk is just what James Horan will want to hear. He has done a fantastic job in the past two years. Last year they defeated the reigning All-Ireland champions (Cork ) and now they have replicated that feat and they have collected two Connacht championships into the bargain.
They are a very committed, talented and organised bunch of players and the way that they have responded to the loss of their captain Andy Moran is admirable. They fully deserved their win in the All-Ireland semi-final and only a sadist would begrudge them an All-Ireland success after 61 years. However, in my opinion, they will have to find another gear if they are going to beat Donegal in the final.
The faded out when they let Dublin hit 0-8 without reply and did not score for 22 minutes which was very worrying and, if they allow something similar to happen in the final, they will be beaten.
But there is nothing definite in sport and that is why we love it.
Based on their respective two semi-final performances, I would expect Donegal to win the final. But we have all been wrong before.
