In the days after Mayo drew the 2017 All-Ireland semi-final with Kerry, I remember thinking the Munster champions were going to bring a different edge to the replay. In Mayo, we would have to be ready.Kerry entered the first game as favourites but on a wet day in Croke Park, we had been able to compete with them across all the key battles. They weren’t going to let that slide. The night before the replay, I told Jason Doherty that Kerry were going to target him. Now, I had absolutely no insight if that was going to be the case, but he had been such a pivotal player in the first game that I felt Kerry would have a plan for him.The following afternoon, as David Gough prepared to throw the ball in to start the replay, a crescendo of noise drew my attention towards the Hill end. The reason for the crowd’s reaction? Jason and Tadhg Morley were wrestling on the ground.But Jason was on top – and in that moment, I knew we weren’t going to take a step backwards that day.I’m not saying that was the reason we won the game, but from our perspective we were sending out the message: “You are not going to intimidate us. We knew this was coming – bring it on."There was a degree of that on show in Killarney on Saturday too.Last year’s All-Ireland final left a mark in the Donegal dressingroom, while the National League decider this season has festered in the Kerry camp since March. It was a humiliating defeat for the Kingdom.On top of that, you had the narrative about Jack O’Connor winning National Leagues and then progressing that same season to win All-Irelands. It all went into the pot ahead of Saturday’s match, as well as Kerry’s proud record in Killarney. That’s before you add in the incident involving Michael Murphy and Dylan Casey from the league final.Donegal's Michael Murphy takes the ball forward against Kerry during last Saturday's All-Ireland Senior Football Championship round-one clash at Fitzgerald Stadium, Killarney. Photograph: James Lawlor/Inpho A jerrycan of petrol was poured over the controversy with declarations by former Kerry players that it wouldn’t have happened on their watch.Mash it all together and throwing the ball in was like tossing a match on a mound of tinder. Up she went.Donegal would have been aware Kerry were likely to come after Murphy last weekend. Because for all the plaudits Kerry get for being the aristocrats of football, you can’t be as successful as they have been without having a hard edge.Players have long memories and you’d be surprised at what they use as motivation. I recently heard Stefan Campbell talking about the 2020 Ulster semi-final between Armagh and Donegal at Breffni Park.I was on the Donegal sideline with Declan Bonner that day and it ended up as a 12-point win. Campbell referenced how the Donegal players had been laying it into the Armagh players about the margin of the defeat.Now, I have no recollection of that and certainly there was no talk in our dressingroom about it. Yet obviously something was said that Campbell took umbrage with, so he grabbed it and stored it away for use on another day.At the top level, you grasp for every inch.So for Kerry, perhaps it was the Murphy incident in the league final or perhaps it was the manner of the defeat. Either way, they brought physicality to Saturday’s contest from the very start.All of that animosity was bubbling away when the game started. For me, the fracas at half-time was the culmination of Kerry – buoyed by their supporters – attempting to make a mark.David Clifford’s late challenge took place just as the hooter sounded. The ball was dead. Therefore, the breeding ground for a row was very much alive. The circumstances allowed for a perfect storm to be whipped up.Referee Seán Hurson speaks to Kerry manager Jack O'Connor (left) and Donegal counterpart Jim McGuinness at the start of the second half of last Saturday's All-Ireland SFC match in Killarney. Photograph: James Lawlor/Inpho If Clifford’s challenge had happened three minutes earlier, the players would have been more game-focused. But because the flashpoint happened when it did, it was like playtime in the schoolyard.Jim McGuinness pushed Kerry player Diarmuid O’Connor. Jim will know, more than anybody, that putting your hand on a player is not the right thing to do, but I have some sympathy for him and I think the context is important.The incident happened in Donegal’s side of the field. They already had one player lying on the ground as a result of the Clifford collision and then Ryan McHugh had become isolated with two Kerry guys at him.If Ryan comes away from that incident unmarked, I don’t think Jim gets involved. But when he sees blood pouring from the side of his player’s face, that changes everything.For a game that is built around brotherhood and that tribal aspect, there is always going to be an emotional element involved. If we don’t want emotion, if we want robotic protagonists, then we’d have a very beige spectacle.If Jim had removed himself from the situation, then everything else that happened still would have happened. And if the Ger Brennan incident in Salthill hadn’t occurred this year, I don’t think this would be such a discussion point now.[ Jim McGuinness made a huge error of judgment – there will be a price to payOpens in new window ]The rule is rigid. A 12-week suspension in a reduced season seems like an overly severe punishment. Perhaps the GAA need to consider introducing a scale of penalties rather than one punitive recourse.If Jim gets a suspension, I think that has a serious impact on Donegal’s championship aspirations. It has the potential to be season-changing.As for the game itself, on Saturday we got to see how everything can change in a couple of seconds.Paudie Clifford of Kerry (right) scuffles with Donegal's Michael Langan (left) and Finnbarr Roarty. Photograph: James Lawlor/Inpho I think Kerry would have been happy enough going in at half-time trailing 1-11 to 0-9. They’d played against the wind but still got 16 shots off. Donegal had 10 shots with nine scores and one wide.Key Kerry players like David Clifford had been on the margins during the first half but they were to have the breeze at their backs in the second half. With an improved conversion rate, I think they’d have fancied winning the game.They had displayed some really good ball-retention and clock-management against the wind, with scores from Morley and Dylan Geaney arriving after lengthy, controlled build-up play.But then the row happens. And the sending-off changes the game. Against the top teams, you must maintain absolute discipline. A red card can be fatal, especially against a team like Donegal whose ball retention is excellent and their ability to manoeuvre players is so on-point. Meath were unable to make an extra man count against Cork, but Donegal won’t let you away with gifting them such a scenario.Just five minutes into the second half, Finnbarr Roarty made a brilliant diving block on a Paudie Clifford shot. Two minutes and 50 seconds later, after some patient build-up play around the arc, Michael Langan kicked a point at the other end for Donegal.Fitzgerald Stadium was baking in the sun, Kerry were a man down and Donegal had started to drag them over and back across the pitch. Chasing that down is energy-sapping stuff.Donegal were so good at managing the clock and you could see the patterns of play they had worked on. With the extra man, it was simply a case of repeat, repeat, repeat.There was a psychological element to the fixture for Donegal as well – this notion that in Kerry there was an air of, ‘You can win your league but when it comes to championship, we dictate the rules here’.So, it was a big statement by Donegal to go down to Killarney and win.I have a feeling the story of this acrimonious rivalry has another chapter or two to run yet this summer.