Casey picked the ball out of his net five times during the final in Ennis last weekend, but it was the concession of the fourth goal on the back of his own intercepted short kick-out that led to the criticisms. The game was level at the time with just minutes to play.
“In fairness, if you're a keeper and you make one mistake, everyone is down on you. But me playing midfield, I'd say I made four or five mistakes but it didn't matter,” said O’Connor who had bagged Mayo’s first three-pointer. “It's tough, it was just one mistake.
“He's human after all. If someone asked me about it after the game, I wouldn't have even noticed it. That's the way it goes, but I'm sure he'll come back better and stronger after it. Cork are no different, they were training as much as we were.
“It's not right any one player being targeted for one mistake he makes on a pitch. It's not right.”
That aside, it has been the prefect week for O’Connor and his colleagues who bridged a ten-year gap to their last All-Ireland success at the grade. More pertinently is the fact that a number of them were on the minor All-Ireland winning crew of 2013.
Winning national finals is not the problem for him, falling at the penultimate hurdle after a replay, which he and Mayo have done twice, is the glass ceiling which must be broken now before that most infamous of curses – and Sam – if lifted.
Transitioning as many of that squad through to the senior grades as possible would go a long way towards. O'Connor, Michael Hall, Stephen Coen and Conor Loftus have all played in the league this year for the seniors. The Ballintubber man can see more treading the same path.
“Oh definitely, 100%. There's a lot of lads there that will be wearing the Mayo senior jersey in the next few years. It's actually a very young team. There's a lot of lads still U21. Yeah, I won't be surprised if a lot of them come through to the senior team, this year or in the next few years.”
Senior manager Stephen Rochford spoke to him after the U21 win and told the 2015 Young Footballer of the Year to take some time for himself before reporting back in for the championship build-up. Not the worst idea given he has exams to sit in DCU next week.
O’Connor didn’t sound this week like a man planning a break though.
Mayo’s Connacht championship defence starts in three weekends’ time against London over in Ruislip and Roscommon’s struggles in New York last Sunday in Gaelic Park have probably concentrated minds considerably on the task at hand.
It’s five years since Mayo’s last visit necessitated extra-time before they claimed the win.
No-one should need reminding of the criticism they faced after that.