To those who were in the ground, it was one of those scores where you knew you had the jump on people watching at home on TV. Just before half-time in the 2012 All-Ireland semi-final, Donncha O'Connor crashed into the rocks of the Donegal defence 30 metres out from goal and when he looked around for help with the erosion, he could find no Cork team-mate to supply the next wave.

Instead he was swallowed whole – all that was left of him was a flailing arm as he fell and the ball that squirted clear to be picked up by Mark McHugh.

The 20 seconds that followed captured Jim McGuinness’s Donegal in all their glory. McHugh scooped up the ball and fed Leo McLoone before breaking his neck to sprint past him. McLoone set off at pace and cut though the middle of the pitch before dishing off to Karl Lacey, also racing past him.

Lacey took a hop and a solo before looping a perfect kick-pass into McHugh, who had sprinted a full 70 metres ahead of where he had picked up the break. The move ended with him casually fisting a point to put Donegal 0-8 to 0-7 ahead. They were never led for the rest of the year. That’s what you saw on TV.

Mugged in possession

What the cameras didn’t catch was the visible breaking of the Cork spirit as player after player was left coughing in McHugh’s dust. When O’Connor was mugged in possession, he was the Cork player who was furthest up the field – McHugh broke out from behind him to gather the ball just as Colm O’Neill was arriving on the scene. Put another way, Mark McHugh passed every outfield Cork player on the pitch between picking up the break and fisting the point.

And they knew it, too. O'Connor had been lobotomised in the gang-tackle so he couldn't chase him, O'Neill had chased back the previous counter-attack and was bushed. Paul Kerrigan was so tired he couldn't bring himself to raise a hand as McHugh slipped his handpass to McLoone and by the time he turned to go after him, it was a lost cause.

Even if the move hadn’t ended without a Donegal score, it was obvious just from watching the Cork attack vainly try to get back that the seal had been broken. They looked like wheezing prison guards trying to run down a jailbreak. They never recovered – not that day, not since.

Everything turned on that game for Cork. They hit snake just as Donegal landed on ladder. In the four seasons leading up to it, Cork had won an All-Ireland, been to a final, variously accounted for Kerry, Dublin and Tyrone and had run up punishment beatings over Donegal, Down and Kildare. More prosaic but no less important was the fact that they very rarely had a moment’s fuss with anyone from beyond the reaches of Division One.

In the four seasons since, here is the list of teams they’ve beaten – Limerick (twice), Clare (twice), Galway, Tipperary, Sligo and Longford. Of those eight wins, three were against Division Four teams, two were against Division Three teams who had been relegated to Division Four that spring. Only one, Galway in 2013, was against a Division Two team.

They haven’t beaten Kerry since 2012 – unless they meet and beat them before the summer is out, they will become the first Cork team to go so long without a win over the Dark Side since late ’70s/early ’80s. They famously became the first Cork team to lose to Tipperary in 72 years. Less heralded perhaps was the fact that they also posted the county’s first defeat to Kildare in 87 years and to Mayo in 95.

“For this team, we just need to beat a Division One team in championship,” said Paul Kerrigan last week. “We’ve come close in the last couple of years, but we just haven’t done it. We need to get over the line. Donegal is the team that has come first to us. Beating Longford and Limerick isn’t the be all and end all for Cork football.

“We need to have a big game, we need to do it for this group. [Donegal] are one of the top five, six teams in the country and that is the level we want to get back to. This is a season-defining game.”

So what happened? First everything, and then nothing. Losing to Donegal didn't mark them out as anything different to the rest of the country in 2012 but it seemed to knock them back further than it did Mayo and Kerry. They won two All Stars in 2012 but by the time the following summer came around, Colm O'Neill was gone to another cruciate injury and Aidan Walsh was trying to be a dual player. As was Eoin Cadogan.

The winter of 2013 saw a job-lot of retirements. Graham Canty, Paudie Kissane, Noel O’Leary, Alan Quirke, Pearse O’Neill – all gone out the door together. Alan O’Connor went as well, although he would return 18 months later. Probably worst of all, Ciarán Sheehen went to Australia, never to be seen again.

Deep panel

As Cork ebbed, the other top teams flowed. Go through the other contenders that year – Donegal, Dublin, Mayo, Kerry. In the four years that have passed, each of them has retained a core of players to build successful sides around. For all the talk of Dublin’s deep panel, up on dozen of their 2012 team are still involved.

The Donegal team that lost to Tyrone a fortnight ago contained nine of the team that beat Cork in 2012, with another three on the bench and Neil Gallagher only missing through injury. The Mayo team that turns out against Westmeath tonight will have anything up to nine of the side that beat Dublin in the other semi-final that year; ditto the Kerry side that went out in the quarter-final.

By contrast, Cork only started four players against Longford a fortnight ago from that 2012 team. Colm O’Neill and Patrick Kelly came on at half-time, Aidan Walsh is back around the place and will presumably see action at some stage. But the point stands – that level of flux is unsustainable.

Yet here they are – still standing on the August bank holiday weekend. Kerrigan harked back to the 2012 game during the week, recalling it as a day that nothing could have prepared them for. That’s who Donegal were in those days. They’re not that now and maybe Cork can find a way against them. But it’s been a long road over the four years, most of it downhill.

“We went with seven forwards against them that day in 2012. We really went for it. The biggest thing I remember from that game is that we stuck to the plan in the first half, but we went away from it in the second half, myself included. Our shot selection and a lack of patience came against us

“They thrived on the couple of opportunities we missed. They feed off momentum. If I get turned over, there will be a big cheer for them. They’ll go up the field in twos and threes, then, and get a score. We just need to be patient. We just need to back ourselves.”

Question is, are they worth backing? Nobody will know better than themselves.