Rivalry has pushed Donegal and Tyrone to drive up standards
Before tonight's Ulster semi-final between the pair, let's look at the last time Donegal beat Tyrone in the Championship. The world of Gaelic football had a long, hard look at itself after that and decided it didn't like what it had become.
That wet afternoon in May 2015 was shocking in the levels of physical exchanges alone, but sickening for the sheer amount of verbals between the sides, their management teams and even wider support groups who got involved in a ridiculous row at half-time as both teams made to get off the pitch and down the treacherously narrow tunnel in Ballybofey.
The following week, 'sledging' was the hot topic. Sean Cavanagh was put up for interview at a corporate gig and said: "Well, there were a few verbals and I was involved in a bit of that. Then, as I turned around, there was a flash point in front of the tunnel. By then I was a fair bit back.
"There was a lot of mouthing, pushing. Sometimes players can normally control each other, but when you see people not normally involved in the game then the whole thing kicks off."
Asked if some players were involved in researching family history in order to find harmful or offensive material on their opponents, Cavanagh added: "Yeah at times, yeah. It can be very, very personal. I know there were certain players, you will probably know, who play for us who have been through tough times, and they were getting a fair bit of personal abuse.
"It's disappointing to see and it's not just all one side. It's both sides. I don't know how you can stop somebody whispering in somebody's ear."
This was the endgame of two teams that had grown to despise each other.
The journey to that point had no real beginning just as it has no ending, but there was a fork in the road when Jim McGuinness took over as Donegal manager towards the end of 2010.
Former Tyrone player Joe McMahon explained: "The big difference in Donegal… as a Tyrone player, you didn't fear them in a sense that you knew their mentality, their attitude, their mental strength wasn't there.
"But 2011 was a turning point. McGuinness touches on that in the book he wrote, about the obsession they had with Tyrone. The obsession paid off. Tyrone were in control in 2011 and Donegal probably thought, 'Here we go again'. But they had a mindset, a belief and a quality at that stage. That day was a massive day for Donegal. They didn't fear Tyrone."
The next year, the giant game of chess in Clones represented the exact point where Donegal wrestled the power for themselves. Donegal's hunger was passed back to Tyrone.
Red Hands boss Mickey Harte had studied Donegal and came to the conclusion that the only way this new and novel side could be beaten was to mirror them. It almost paid off too as Martin Penrose's fizzing shot was heading for the corner of the net at the death only for Donegal goalkeeper Paul Durcan to get a toe to it.
The year after that, goalkeeper Niall Morgan came in for free-kicks. It ended badly.
"Donegal were up there and were the team everyone looked to beat. It was just a complete role reversal. The obsession was there," stated McMahon.
"I remember us going to Ballybofey to play them and I have an image in my head of someone standing at the door of a house pointing out the back as if we were headed for the back door. That stuff was always there in the border towns."
That pattern continued up to the 2016 Ulster final. Late points from Cavanagh, Peter Harte and Kieran McGeary landed like gifts from the heavens to finally break the curse.
"The elation in the changing room and the celebrations afterwards, there was just this emotion. There had been dominance from Donegal and they had all this success, up there just like we had been. That day, it was total obsession from the squad to achieve what we set out to do," said McMahon.
"All the frustrations had come through and we toppled Donegal. That day was a great confidence boost for young lads coming into the squad who had never beaten Donegal. It was huge pressure off the shoulders."
And off the manager, Mickey Harte.
"You have everything done, all the video analysis, the homework, it's all gone. It's a matter then of putting it into a performance," said McMahon.
"Mickey had us so well drilled. Before the game, he'd talk to the different lines of the field about the expectation. He posed questions in terms of what Donegal would be thinking, some questions about different scenarios. It was a case of, 'We have met this before, we know how to address it'."
Tonight, they are just too finely poised. The latest chapter will be written and nobody would be surprised at either outcome.
As McMahon said: "It's almost become like a club rivalry, it seems very parochial.
"I think the pressure is off Tyrone this weekend, but Donegal are sitting quietly and that's a danger for me."
The Ulster Championship at its very best. The 'real final?' For sure.