The 30-year-old stepped onto his home course as tournament favourite, as Portrush hosted The Open for the first time in 68 years.
McIlroy shot 61 aged 16 on these Dunluce Links, but blew his latest tilt at a second Open title with a woeful eight-over 79 in Thursday’s first round.
A horror-show quadruple bogey at the first and a triple bogey at the last offered McIlroy a brutal bookend, leaving the home favourite scrambling even to make the cut.
Asked if he can find any way back into this tournament, McIlroy joked instead about going back to his United States base, quipping in reply: “Definitely away back to Florida.’’
But quickly changing tack, McIlroy continued: “Look, I definitely think if I can put the ball in the fairway tomorrow I can shoot a good enough score to be around for the weekend. Obviously I’m pretty sure anyone starting with a 79 in this golf tournament doesn’t think about winning at this point.
“But I think I can go out there and shoot something in the mid-60s, be around for the weekend, and then try to play good from there.
“I guess when you play your first and last holes in a combined seven-over par, you’re sort of starting on the back foot.
“It was a rough start. But I felt like I showed some good resilience after that.
“I think I played the next 13 or 14 holes at two under par. And then really what I’m disappointed about is I undid all that great work over the last few holes.
“I lost concentration after the missed par putt on 16, I missed a short one there. And then on 18, I hit a tee shot that I knew wasn’t going to be in the fairway, but I didn’t think it was going to be quite as bad as it was.
“I’ll dust myself off and come back out tomorrow and try to do better.”