The world No.11 is not afraid to admit the scars of his opening round of 79 in the last Open Championship to be played two years ago remain raw, as he fluffed his lines on a course he knew so well.
It's not just that this was another major that slipped through his fingers. This was the one that meant more, in front of his own people and with the most intense spotlight falling on him.
And that may be why it went so wrong so quickly.
McIlroy had set his sights on winning his second Claret Jug in front of his home fans at Portrush long before he returned to his homeland but, as he admitted, the weight of expectation has got too much for him.
A second round of 65 left McIlroy one short of the cut mark and departing back to his adopted American homeland regrets aplenty, as he confirmed in an interview that saw him breaking down in tears as he tried to sum up his failure to make the most of a chance to shine on home soil.
The iconic victory for compatriot Shane Lowry at Portrush left McIlroy to look in on what it was like for a local here to win The Open in Ireland and two years on, he admits his opening round at Portrush has left a lasting legacy.
Speaking at an event to launch GolfPass on Sky Q in Ireland, the four-time major winner admitted he has thought long and hard about what went wrong on a course he knew so well and he hopes the experience has allowed him to grow as a golfer.
"I didn't approach Portrush the right way in terms of preparing myself to play in that atmosphere in front of those people," he told us.
"It was almost as if once that first round was out of the way I was unburdened because I was like 'I can't win from here' and then I go out and shoot 65 on the second day.
"It's trying to feel on the first day how I felt on the second day, that's the key. That's just unburdening yourself.
"There are certain things you can do, mental exercises, to get into that frame of mind but in Portrush that week I didn't do a good enough job and I learned from that and it's something I've tried to improve on since."
Form is crucial heading into a major, yet McIlroy has been struggling to find a consistent rhythm in his game over the course of 2021.
He admits he was caught up in a macho battle to compete with big-hitting Bryson DeChambeau in the ball speed statistics, with his wayward driving a big factor in his inability to string four consistent rounds together.
McIlroy has been working with his coach Pete Cowan on his driving in recent days after a poor showing at last week's Irish Open and he is hopeful of getting himself in a position to challenge for the Open when it gets underway at Royal St George's next week.
"I know why I was not driving the ball so well and that's half the battle," he continued. "I met up with Pete on the range here in Scotland on Tuesday morning and we did some good work.
"It is just a matter of going out on the golf course and trusting it and we are certainly in a better place than we were leaving Mount Juliet last week."
While McIlroy has not got his hands on the Claret Jug as Open champion since 2014, he believes his experience growing up on links courses gives him an edge on his American rivals in what has become the final major of the golfing year.
His three top five finishes in Open Championships prior to his nightmare at Portrush in 2019 cements his belief that he can make a push for glory in the tournament that gets underway on Thursday.
"I know how to play links golf, I grew up on it," he reflected. "I know how to play Open Championships. Portrush wasn't what I wanted but I've had a win, a second and three other top fives.
"I feel comfortable in that environment, it's been nice to get back to links golf in Scotland as I've not played links golf for two years so to familiarise myself with it has been nice.
"I'd have previously said in my career the Open was not the major which suited me the most but results say otherwise."
McIlroy was speaking as he helped to launch GolfPass in Ireland on Sky Q, with the interactive golf service offering a range of viewing delights for fans of the game.
Subscribers can watch daily golfing tips and hundreds of exclusive videos, bringing you closer to the game you love, at home, in an informative, fun and interactive way.
"I've been involved with GolfPass for the last couple of years and now it is available on Sky Q," he added.
"We are trying to bring golf into the 21st century, bring the game forward and make it more accessible.
"We have instructional videos on there, interviews, a lot of cool things on there and I'm happy to be a partner. Hopefully we can go from strength to strength and hopefully people on Sky can start to enjoy it in Ireland and the UK now.
"One of the silver linings from Covid is the uptake in participation at golf courses and we have to find how we can keep it going. An initiative like GolfPass can really help this.
"We need to make golf accessible, especially the younger generations and that's where this can be really helpful.
"A lot of the best instructors and players are on GolfPass and I've realised over the last few years how good the game of golf has been to me. Never did I believe I would be here sitting in the position I am. This feels like a way of giving something back to the game.
"There are a lot of places in the world where golf is an aspirational sport. We need to break down those barriers, so hopefully GolfPass can help with that."
GolfPass is available in Ireland on Sky Q now.