It will be hot and heavy in Enniskillen and that will suit Rory Gallagher and Fermanagh
On Sunday, Brewster Park will be a tinderbox. It won't take much of a spark to set fire to what is a rapidly burgeoning rivalry.
It wasn't always the case but there's a significant amount of tension now when Donegal play Fermanagh.
The Rory Gallagher connection has contributed to that, as has the amount of times they have met in recent seasons, a bit of familiarity breeding contempt. We saw that during the league with the fracas in the tunnel at half-time in Letterkenny.
That largely escaped the attention of the national media but they cut lumps out of each other at the short whistle. Players have long memories for that sort of stuff. No doubt there are scores to be settled from that day.
And if it's a feisty, contrary sort of game then I don't think Gallagher will mind because he knows better than anyone just what sort of talent his side are facing when they play Donegal.
I don't say this lightly but in terms of natural talent, Donegal are better equipped than anyone in the province. Their overwhelming instinct is to attack. Even their best defenders like Eoghan Bán Gallagher and Ryan McHugh (if he's played in the half-back line) love to bomb forward.
So if Fermanagh can turn it into an arm-wrestle, they'll be quite happy. It will be a very tactical game. Donegal will dominate possession but will face a wall of 15 Fermanagh jerseys for most of the 70 minutes.
If their tactical approaches are different they have one thing in common - their biggest strength is also something that could be exploited.
In Donegal's case, that's Michael Murphy. He is the heartbeat of the time. And if he plays well, Donegal generally win.
Between winning and scoring frees, setting up the play or finding his range himself, he's probably directly involved in around 70pc of Donegal's scores.
But when he's out of the team or kept quiet, Donegal have shown themselves to be vulnerable. They lost to Tipperary and Fermanagh and were struggling at home to Armagh on the night Murphy made his seasonal return.
They won that game with Murphy getting the crucial goal and went on to win the Division 2 final, with Murphy giving an exhibition in the decider. Fermanagh's first task will be to limit his influence.
Fermanagh are similar except their weakness also helps to make them competitive.
Their playing population is significantly smaller than most but that's also the reason why they'll go the extra mile.
I worked with the footballers in Fermanagh and I can tell you Gallagher will have had no problem selling his style of football to them.
When you're playing football for Fermanagh you're already facing an uphill battle. If there's anything that can be done to level the playing field a little then those fellas will do anything you ask of them. They can take hope too from that league game.
Fermanagh won 0-13 to 0-10, their first league win over the Tír Chonaill men in 40 years.
It was also a dry run for what we'll see on Sunday in that there were 14 yellow, one black and one red card shown that day.
I don't see Fermanagh making the mistake of the Ulster final last year where they conceded an early goal and were chasing shadows for the rest of the day.
Brewster Park is a tighter pitch than Clones and it will be easier to impose their style on the game.
It will get hot and heavy and cool heads will win the day.
Staying detached on the sidelines is one of the hardest things to do especially when there's an edge to the game. Managers and selectors can get caught up in what's happening off the ball or in referees' decisions.
Staying focused enough to see trends and make clear-headed decisions is crucial and in that regard Stephen Rochford could play a big role for Donegal.
He should be more emotionally detached from the game to see those patterns. It will be a game of small margins so all those little things count.
Donegal can come out on top but only after a stern examination.
The other Ulster quarter-final sees Tyrone take on Antrim tomorrow night.
The big news for Tyrone this week was the decision of Lee Brennan to leave the squad. I worked with Lee on the U-21s in 2015 and know it's not a decision he would have taken lightly but I can understand it.
When you're outside the first 22 or 23 on the panel and making all the same sacrifices as everyone else it not's an easy place to be. But he'll look after himself, work on his game and I've no doubt we'll see him in a Tyrone jersey again.
As for the clash with Antrim, Tyrone should have enough. I attended the Saffron Business Lunch last weekend. The event was superbly organised by a group of Antrim Gaels, determined to get the county moving in the right direct both on and off the pitch.
Short term, their difficulty is getting all of their most talented players to buy in.
Until that changes, it is very difficult to see them playing up to their true potential.