Tom McKibbin was best of the Irish on one under par following the opening round of the PGA Championship at Quail Hollow.
The Holywood club man got over a shaky start at the North Carolina track, opening with a bogey five on the par-four first, however, he settled into his round with a run of five straight pars.
Back-to-back birdies then followed on the seventh and eighth as McKibbin reached the turn on one under.
But again, a bogey arrived to begin the back nine to drop back to level par, before McKibbin bounced back on the short par-four 14th with another birdie.
McKibbin then took full advantage of the par five 15th by reaching, more or less, in two.
Just off the green to the right and he played a most delicate chip down to the hole, almost making eagle from the deft touch, tapping home for birdie to get to two under.
Two pars would follow on 16 and 17, however, a wayward drive on 18 left him with no option but to chop out onto the fairway before playing his third onto the green.
McKibbin was unable to make the par putt and signed for an impressive one-under 70 and sits six shots off the overnight leader Jhonattan Vegas who grabbed the first round lead with three late birdies to open up a two-shot advantage over America's Ryan Gerrard and Aussie Cam Davis, who both shot five under.
Rory McIlroy is well off the pace after an underwhelming start in North Carolina.
Following his emotional Masters triumph at Augusta a month ago, McIlroy was among the favourites for the year's second major, played on a course where he has achieved four wins on tour.
However, McIlroy hit just three fairways in regulation and was fortunate not to find the water with a number of pulled tee shots in an unexpectedly poor display.
Playing in the headline grouping alongside Scottie Scheffler and defending champion Xander Schauffele, McIlroy opened with a birdie on the par-5 10th but quickly gave it back with a three-putt on the 11th.
He got back under par with another par-5 birdie on 15, after flirting dangerously with the water down the left side - a theme throughout his opening round.
However, that was as good as it got for Mcilroy, who endured a disastrous 16th hole after pulling his drive miles left. From a hanging lie in dense rough, his back foot slipped and he could only advance the ball 20 yards to the brow of the hill. From there, he pushed his third right of the green and made double-bogey.
He was in good company on a notably treacherous hole, Scheffler and Schauffele both finding the lake with their approach, the much-vaunted trio treating the galleries to three double-bogeys on the hole.
Scheffler, who was infamously arrested before the second round at the PGA Championship last year, dug in on the inward nine and battled to a two-under par 69.
Schauffele also steadied the ship on the way home, notching a birdie on the eighth and parring the rest of his homeward nine to card a one-under par 72.
McIlroy, however, couldn't wrestle back any momentum, bookending his back nine (the course front nine) with dropped strokes, failing to save par from the sand on the first hole, concluding with a bogey on the ninth after another wayward drive.
Shane Lowry finished one stroke better off on two-over par, battling back somewhat after a rocky start.
Four days after an agonising near-miss at the Truist Championship and playing on a course where he had "no record", Lowry was three-over thru seven holes.
He had blown a birdie opportunity on the driveable par-4 14th, following that with two successive bogeys on the par-5 15th and the ferociously difficult 16th.
However, he hit a purple patch around the turn, clipping a fine approach into four-feet at 18 for his first birdie.
And while he dropped another stroke at the first, he followed that with successive birdies on the third and fourth, the latter a monstrous 68ft putt to get back to one-over.
With momentum on his side, Lowry missed big birdie chances to get back to even par at the seventh and eighth before concluding on a bum note. After finding the bunker off the tee, he wound up with a closing bogey to sit on two-over par.
Seamus Power finished best of the early Irish starters, after a rollercoaster outward nine.
Power, who finished tied ninth in his first PGA championship at Southern Hills in 2022, recorded two double-bogeys, two birdies, an eagle and another bogey in his opening seven holes.
The eagle arrived - with Power at +2 - at the driveable 311 yard par-4 14th, with Power finding the green and trickling a hard-breaking downhill putt into the hole.
That gave way to a steadier inward nine, Power registering seven pars, alongside one birdie and a bogey to finish with a one-over 72, six strokes off the lead.
2008 champion Padraig Harrington, the earliest Irish starter, carded a two-over par 73. Harrington, the first post-war European winner of the event at Oakland Hills, briefly got under-par with a birdie at the eighth but followed that with four bogeys in a row around the turn.
A birdie from the greenside bunker on the par-5 15th got him back to two-over par after Round 1.
The quintet of Ryan Fox, Alex Smalley, Stephen Jaeger, Aaron Rai, and European Ryder Cup captain Luke Donald, share fourth place, three off Vegas..
Donald, who finished tied-third in Medinah back in 2006, admitted he was chuffed with a blemish free round.
"Obviously very pleased with the score, bogey-free in a major," Donald said after getting up and down from a bunker on the 18th to complete his superb 67.
"Someone just told me it was the lowest first round in a major I've had since 2004 or something. Obviously I’ve been trending with all the missed cuts coming into this week!
"But no, it was a pleasant surprise. I got off to a really nice, steady start. I hit a bunch of fairways on the front nine which always makes me feel good about my game.
"I didn’t hit a ton of greens today, but my putter was really good. Not surprisingly the greens were infinitely quicker this morning first group out than they were the last few days [after all the rain].
"But I adjusted very well to them and I made a lot of good, solid putts out there."
His opposite number in Bethpage Black, Keegan Bradley, winner in 2011, is only a stroke further back after an opening 68, part of the group on three-under, which includes Matt Fitzpatrick and Bob McIntyre.
Additional reporting: PA
