The world No 1 carded his worst first nine of the season, reaching the turn in 41, and never recovered as he shot a nine-over 80 – his highest round since the final round of the 2011 Masters. ??
Both McIlroy and Ryder Cup team-mate Martin Kaymer failed to post a single birdie in windy conditions at Royal County Down, as playing partner Rickie Fowler opened with a level par 71 to stay within three of the early lead.
McIlroy came in to the event having missed the cut in his defence of his BMW PGA Championship title last week and despite insisting he felt refreshed after an unexpected weekend off, opened with a missed 15-foot birdie chance at the 10th and a dropped shot at the next.
The tournament host found the par-five 12th green in two but could only three-putt from long range, before things went from bad to worse with a run of four consecutive bogeys from the 15th.
After finding the bunker off the 16th tee and making another three-putt at the 18th, McIlroy eventually stopped the rot with a two-putt par for par at the first. ??
The four-time major winner slipped further adrift after missing the green at the par-three fourth, adding a seventh bogey of the day at the next when a clumsy chip left him a long way from the flag.
A 12-foot birdie putt at the sixth appeared on line before slowing inches short of the cup, with McIlroy sending his tee-shot on the par-three seventh onto the wrong fairway to card another blemish.??
McIlroy bogeyed the eighth but looked set to make his first gain of the day at the par-four ninth, finding the green in two before sliding his birdie putt several feet past the cup.