Our Gaelic Games correspondent tackles all the battles in the big game both on and off the field.
Colm McFadden v Philly McMahon
It's a massive ask for any player to catch fire on the one particular game you need him, knowing your team’s fate will probably be decided by that one performance.
Because it really is that stark for Donegal; if Colm McFadden fails to reach something of his form of 2011 and 2012, then they do not have a hope of beating Dublin. Jim McGuinness' talents in motivation are legendary by this stage, but he is going to have to use everything in his power to get a reaction from McFadden.
In public, he has backed him to the hilt and reminded us of what he has been capable of in the past, and Kevin Cassidy has said Donegal fans should be grateful to McFadden as they would never have won their second All-Ireland without him.
However, he is a declining force and exactly the kind of player that Philly McMahon would thrive against.
Rory Kavanagh v Michael D MacAuley
With Neil Gallagher a most traditional midfielder, he will be in the centre for the variety that his high-catching gives Donegal, along with the assured fielding on the edge of the square while under pressure.
But Donegal need somebody mobile in midfield to cope with the athleticism of Michael Darragh Macauley. The Ballyboden man has dominated all of his personal tussles this year and the best way of tapering his influence could be a job-share arrangement in the Donegal midfield.
For that reason, Jim McGuinness may start Martin McElhinney in midfield with Rory Kavanagh coming on at half-time or shortly after. The St Eunan's man has been vital to Donegal since developing into the midfield role and McGuinness has trusted him to be the steadying influence for their traditional, big third quarter. His speed and lungs will be needed for a frantic finish.
Neil McGee v Eoghan O’Gara
In a forward line of such artistry, Eoghan O'Gara sticks out in the Dublin attack. He does not possess the same talents as Diarmuid Connolly and Bernard Brogan but he is, nonetheless, just as important.
When Dublin choose to go direct, it is to O'Gara they aim their passes. Fleet of foot and strong of upper body, he can hold off his marker, collect the ball and wait for Connolly, Paul Flynn or Kevin McManamon coming off the shoulder to shoot, or else can turn inside and deliver to either Brogan brother.
However, there are few defenders as fast as Neil McGee and in the upper body strength stakes, his is as solid as Mount Errigal. If Donegal are double-teaming other Dublin forwards, then this could be a one-on-one battle.
Dublin will be anxious that O'Gara's discipline can hold as McGee is sure to give him a hard time.
What Donegal need to do
When Dublin lose the ball, they have adopted the Barcelona approach of pressurising high up the pitch. Their forwards harry as if their continued participation on the pitch depends on it, which of course it does.
However, when Monaghan were able to carry the ball through that initial tackling phase, they found things opened up a bit for them in the middle third of the field.
Donegal have not had their counter-attacking game moving as fluidly as 2012 with a lot of spilled ball, handling mistakes and rushed shot selections. The training camp in Johnstown House would have highlighted and examined this.
The deployment of Michael Murphy will be of interest. In the 2011 game Donegal yielded only 0-6 and with Murphy playing in midfield they lost so much attacking potential. With Colm McFadden unable to lead the line on his own, Murphy will have to go up top for at least a decent spell to face down Rory O'Carroll.
What Dublin need to do
When Jim Gavin says Dublin have been preparing for this challenge over the last couple of weeks, he is deliberately misleading us.
The truth is Dublin will have dissected Donegal's system for a long time now, given that Gavin's coaching centres on the foundations of 'repetition, repetition, repetition.'
It was felt that Monaghan would give Dublin something of an idea of how to play against Donegal and, after 25 minutes, the floodgates opened. Sure, the Ulster champions will be organised but there is a sense each player could be so tied up in his own personal battle the game could turn loose very quickly.
Patience is a necessity, and Dublin may have to rely on the long-range kicking skills of Paul Flynn and Diarmuid Connolly to get them in front.
Once they have the lead, Donegal will surely have to come out of their defensive shell. In such circumstances, their limitations can be exposed, especially on a pitch that plays this fast.
The game in numbers...
26: Dublin's average number of points per game this year, give or take a few percentages. Should they maintain that average on Sunday they will win. Donegal's average score this year is 17, while the average concession of scores is just over 12.
The man in the middle
Joe McQuilan (Cavan)
Was in charge Armagh v Donegal and many neutral observers were amazed at the lack of cards handed out to Donegal players. Has also taken charge of in-house Dublin matches.