David Coldrick needs to sleep soundly tonight because it's vital that he is fresh and ultra-alert tomorrow.
At 2.0, he will take control of Armagh v Donegal, a game laced with so many combustible possibilities that however many are addressed, several others will most likely be missed.
The Armagh-Donegal All-Ireland quarter-final in Croke Park last August was a feisty affair and, in the far more claustrophobic atmosphere of the Athletic Grounds, there's every chance that the temperature will rise even further.
Whether it reaches boiling point or beyond remains to be seen, but, with the stakes so high, it will be no surprise if Coldrick has a very busy time, especially early on when markers are being hammered down.
There was intense focus on last month's Donegal-Tyrone game ever since the championship draws were made in October but, for all the intensity of that busy rivalry, it has maintained a reasonably smooth course over the last decade.
Besides, the last two Donegal-Armagh games were in Ballybofey, giving the home side an advantage that they exploited on both occasions.
Now Donegal must go to the Athletic Grounds for what will be Armagh's first championship game of Kieran McGeeney's managerial reign.
He was, of course, working alongside Paul Grimley last year, but this is much different. It's all about McGeeney's philosophy now and whether he can build through the provincial system, an objective that eluded him in Kildare, who reached only one Leinster final during his six-season term in charge.
Indeed, Wicklow and Louth enjoyed championship wins over Kildare in two of the first three years under McGeeney.
His success in turning Kildare into such a formidable qualifier power was impressive, but provincial fields remained largely barren for the Lilywhites.
History shows that the first season can be hugely important for a manager. Kildare suffered an opening round Leinster defeat by Wicklow in McGeeney's first term (2008), but rebuilt in the qualifiers, eventually reaching the All-Ireland quarter-finals for the first time.
It was an important recovery, something which they perfected in subsequent seasons, so that by the time McGeeney departed, Kildare had reached five quarter-finals, via the qualifiers.
Donegal took Ulster by storm in Jim McGuinness' first season as manager in 2011, powering to the title by winning four times, after conceding just under nine points per game, thanks to his ultra-defensive strategy.
The success was all the more remarkable since 11 of the Donegal team that started the 2011 Ulster final had featured on the side that lost to Armagh by nine points in the All-Ireland qualifiers a year earlier. Essentially, all that had changed was the manager and the different culture he brought to the camp.
Despite being in Division 3 this year, Armagh are further ahead of Donegal than when McGuinness took over in the north west in late 2010.
Armagh took 2013 Ulster champions Monaghan to a replay in the semi-final last year and later beat Tyrone, Cavan and Meath in the All-Ireland qualifiers, before losing by a point to Donegal in the quarter-final.
It left Armagh with a fourth to eighth place finish in the All-Ireland race, territory also occupied by Galway, Monaghan and Cork.
All of which suggests that despite attempts by Armagh to portray themselves as being in the early stages of a work-in-progress, they are quite well advanced.
McGeeney is even playing down home advantage, suggesting that the Athletic Grounds is a better fit for Donegal than Armagh.
"Clones and Croke Park probably suits our style of football more. The tight pitch (Athletic Grounds) might suit Donegal more. We played them there in the league last year and you could see it definitely suited them. It's a tight pitch and I think it plays tighter because the wall is close to it," he said.
Now, if McGeeney really believed that the venue was a plus for Donegal, he wouldn't have pumped it into the media mainstream. After all, why make Donegal feel any better about themselves?
Unless, of course, you wanted them to believe something for which you have set up an elaborate ambush. In any event, how could home advantage not be a bonus for a team?
Armagh v Donegal is the fifth game in the Ulster campaign, three of which (Donegal v Tyrone, Cavan v Monaghan and Derry v Down) have been very close-run affairs. And while Fermanagh beat Antrim by 10 points, it was only on the home run that they extended what had been a two-point lead after 60 minutes into a sizeable advantage.
Contrast that with events in the other three provinces, which have already thrown up some very one-sided games and, no doubt, there are more to come.
It's why in all the on-going debates about championship structures, one point continues to be missed. One of the GAA's provincial fields remains hugely fertile, returning high yields on an annual basis.
The other three may have a lot of stony soil, but that's nothing to do with Ulster, which ploughs a productive furrow. Of course, it's not without dark side, having acquired an unfortunate reputation as Sledging Central, scarcely something to be proud of, irrespective of the many other virtues it possesses.
Still, in terms of competitiveness, Ulster is well ahead of the other three, but then that's reflected in Allianz League placings too.
Eight Ulster teams will be in Divisions 1 and 2 next year, with only Antrim (Division 4) in the bottom 16. Donegal, Monaghan and Down will be in Division 1; Armagh, Cavan, Derry, Fermanagh and Tyrone will be Division 2.
Contrast that with Leinster, where Dublin will be the only Division 1 side and where eight (Carlow, Wicklow, Louth, Wexford, Kildare, Westmeath, Longford and Offaly) counties will be in Divisions 3 and 4. It's hardly surprising then that the Ulster Championship is more appealing.
With the exception of Antrim, there's a real sense of solidity across Ulster. The days when their championship was seen an irrelevant sideshow to the main All-Ireland event are long past, an achievement brought about by the determination within each county to get the very best out of itself.
In that sense, Ulster puts the other provinces, especially Leinster, to shame. How can Ulster have eight of nine counties in the top 16 in the league, while Leinster (excluding Kilkenny who don't compete) have only three?
There's no logical explanation, which is why Ulster bristles at suggestions that the All-Ireland format be changed. They see it as a knee-jerk reaction to one-sided games in other provinces, rather than a thoughtful analysis of the overall scene.
The Ulster view is that if the other provinces were as competitive as theirs, there would be no need for the constant debate on All-Ireland structures. It's a fair point.
Against that background, there is absolutely no chance than any Ulster county would vote for any championship system that didn't hold the provincial system as the foundation of the All-Ireland structure.
While winning provincial titles may mean little to Dublin, Kerry and to Mayo nowadays, claiming the big Ulster prize will always remain extra-special, even for the likes of Armagh, Tyrone and Donegal, all of whom have won All-Ireland titles over the past 12 years.
That's why Armagh and Donegal see tomorrow's game purely in Ulster Championship terms. It's also part of a bigger picture, but that can wait. Local pride comes first for now.
It what makes the Ulster Championship the undoubted success that it is.
Figures show the average winning margin per game in the provincial football championships over the past five seasons and, separately, for this year.
Ulster leads the way comfortably for the tightest games, followed by Connacht, Leinster and Munster. New York's games are not included in the Connacht figures as they would distort them. New York do not compete in the Allianz Leagues, leaving them at a serious disadvantage when it comes to preparing for the championships, so it would be inappropriate to include their annual Connacht game in the averages, since they usually lose by a very big margin.
Ulster continues to lead the competitiveness table this year.
Average Winning Margin: 2010-14
Average Winning Margin 2015
Naturally, Cillian O'Connor is a little uneasy. Just slightly. His last league game was on March 8. A knee injury required two months' rest. Most of his training was restricted to gym work and off-field conditioning. He has only three weeks field training under his belt. Fifteen minutes of a club championship game. One half of a challenge game. An A versus B training game last weekend. With Galway coming down the tracks, of course O'Connor wanted more.