Rory McIlroy begins the Irish Open four shots off the lead after an opening 18 that stretched beyond six hours in gusting wind and persistent rain. The world number two signed for a one-under-par 69, opening with birdies at the second and fourth holes, dropping a double bogey at the 13th after two attempts to escape a bunker, then answering with a birdie at the 15th.

McIlroy described the round as unusually protracted and stop-start, saying, "I can't recall a round of golf that has taken that long before. We've had some rounds that have taken five and a half hours or maybe five and three quarters, but over six hours might be a first for me." He added the weather made club selection and rhythm hard to find, "It was tough conditions, very windy, it was hard to get into any sort of rhythm out there, it was kind of stop start, so I felt like shooting under par wasn't exactly what I wanted, but at the end of the day I'm only four shots behind and not in a bad spot going into the next three days."

He also quantified the wind's effect on yardage, saying "You were hitting into the wind on average three or four clubs more than you usually would. I had 138 yards to the last green there and hit my full seven iron. I usually hit my seven iron in warm, dry conditions 190 yards." Those adjustments help explain the ragged scoring across the leaderboard.

Chile's Joaquin Niemann leads at five under after an opening round that produced six birdies and a single dropped shot, including a run of four straight birdies from 14 to 17. A cluster of players sits on three under — Ireland's Shane Lowry, South Africa's Shaun Norris, Renato Paratore, Maximilian Steinlechner and Adrian Meronk — though several of them will need to return on Friday morning to complete holes left unfinished when play was suspended because of fading light.

Late starters were particularly disadvantaged by the conditions and the loss of daylight. Tom McKibbin is among those on two under after a strong start, while Jon Rahm managed a level-par 70. Robert MacIntyre is two over, Sergio Garcia and Brooks Koepka sit at +5 after difficult openings, and Tyrrell Hatton is eight over.

McIlroy heads into the remaining rounds attempting to defend the title he won at the K Club last year and chase a third Irish Open victory, one that would draw him level with Seve Ballesteros, Nick Faldo, Bernhard Langer and Colin Montgomerie on three wins in the event. Players who left holes incomplete will return on Friday morning to finish their first 18 holes before normal play resumes for the second round.