Our Gaelic Games correspondent Declan Bogue tackles all the battles in the big game both on and off the field.
Eamonn Magee v Kieran Hughes
Eamonn McGee is the tallest defender in the Donegal camp, but he will have bad memories of the three points from play that Hughes scored in last year's decider. If Hughes is struggling with an injury, McGee will look to test it early on. There is no question that Donegal will give their full-back line more protection this year after Monaghan's fast start gave them the confidence to go on and win the 2013 final.
Hughes' ball-winning ability is among the best in the game as he has elusive movement and speed, but perhaps his greatest talent is his leap. As a matter of fact, it was his vertical jump readings that piqued the interest of Aussie Rules scouts when they held a training camp a few years ago in Jordanstown. He has been struggling with a jarred knee since the Tyrone match and had to be withdrawn in the semi-final replay win over Armagh at half-time.
Odhran MacNiallais v Ryan Wylie
In the three games to date, Wylie has picked up Tyrone's Darren McCurry, before looking after Kyle Carragher and then Tony Kernan against Armagh. With Donegal's inside forward line of McBrearty-Murphy-McFadden so well looked after by Walsh-Corey-Drew Wylie last year, Monaghan would be loath to change a winning formula, so Ryan will play deeper.
With burning pace and fitness a huge strength of these two, they will cover the entire pitch. Should MacNiallais drop deep, Wylie will let him go, but will push up for Donegal kickouts in order to prevent cheap possession.
With Rory Kavanagh, Neil Gallagher, Christy Toye and Martin McElhinney all vying for a place in midfield, it seems likely that MacNiallais will be pushed into a wing-forward slot. A classy performer with a lovely left foot and a sweet kicking action, he is an athletic and tall presence that Donegal will not wish to lose around the middle third.
Michael Murphy v Vincent Corey
Any one of the Donegal front three could have been chosen for this as their record last year was poor. Neither Paddy McBrearty or Michael Murphy scored at all in the corresponding final, while Colm McFadden was restricted to four points from the dead ball as Drew Wylie kept him on his weaker right foot throughout.
Murphy has yet to hit previous heights and was well-shackled in the semi-final, but his positional sense will cause a headache or two for Monaghan.
Corey has been lining out at centre-back all season, now that Neil McAdam is in Australia. In the first game against Armagh he experienced difficulties against Kevin Dyas, but recovered well to dominate their tussle in the replay. To move him out of centre-back is to slightly distort their shape, but it is a risk that Malachy O'Rourke would be willing to take. In his absence on the ‘40', Dessie Mone could pick up Leo McLoone.
While Monaghan have been battle-hardened by three tough Championship games and domestic league games, Jim McGuinness has had almost exclusive access to his players, so something new is definitely expected here.
Among the switches they could make is to move Karl Lacey to mark Conor McManus. After scoring 1-7 the last day out, Donegal cannot afford to allow this to happen to them and Lacey is an expert man-marker.
McGuinness also needs to make a tough call and a selection surprise could be starting Darach O'Connor ahead of the out-of-sorts Patrick McBrearty, who has tended to play his best football this year coming off the bench. O'Connor meanwhile is so unpredictable that Monaghan could initially struggle to figure him out.
Another tricky call is determining if Rory Kavanagh will be sharpened enough to start in a midfield that might not match up to Monaghan's. And finally, they cannot afford to go four down in the first 10 minutes like last year's final.
First of all, Monaghan needed to have spent some time this week reminding themselves that they are, in fact, the Ulster champions. The odds are not that far apart, but Donegal have been made favourites despite not truly being tested in the Championship, while Monaghan came through three big tests.
They need to protect Rory Beggan as he advances to take frees and not allow Donegal to bully him like they did to Niall Morgan last year.
Presuming they repeat the match-ups in the full-back line as last year, they need to get the same return; which was holding McBrearty, Murphy and McFadden scoreless from play.
The half-forward line will need to be alert to break up Donegal attacks generated by the likes of Thompson, McGlynn and Ryan McHugh.
While the ball into Kieran Hughes and Conor McManus needs to be early, plenty of support needs to arrive on the scene before Donegal get their defensive shell in place. For that reason, Paul Finlay's long-range shooting could be key.
The man in the middle
Maurice Deegan (Laois)
Should he choose to take a dim view of the Donegal swarm tackling, then the kicking skills of Rory Beggan could well decide this game. Has handed out more than the average number of black cards this season.