Rory McIlroy is three shots behind leader Xander Schauffele in second place after the first round of the Wells Fargo in Charlotte.
The County Down man had a strong start to the tournament with an eagle, three birdies and one bogey through the first nine holes, but slipped with three birdies and three bogeys on the back nine.
He finished with a four-under par 67, putting him tied in second place with American Collin Morikawa and Sweden's Alex Noren.
A fine start for Seamus Power was cancelled out by a nightmare finish to his opening round.
After opening with successive birdies, Power remained at two-under by the turn. Things improved again at the par-four 13th and again successive pars moved him high up the leaderboard before coming a cropper in the final three holes.
The 37-year-old found the rough at the 16th and three-putted his way to a double bogey, and followed that up with a dropped shot at the 189-yard par-3 17th.
Any hopes of ending on a positive note were dashed after a wild second shot at the last that left his scrambling his way to a second double bogey in three holes to finish with a one-over par 72.
Shane Lowry laboured to a four-over par 75 after a challenging day.
The Offaly man, in attendance courtesy of the recent Zurich Classic of New Orleans team event win at TPC Louisiana alongside McIlroy, couldn't find any rhythm from the outset.
Starting at the 10th, a couple of bogeys in the first five holes had the former Open champion on the backfoot along with a double-bogey at the 17th – his eighth – after finding water off the tee.
The front nine was a steadier affair, a bogey at the first immediately followed by a birdie after a superb approach shot allowed him a four-foot putt to pick up a shot.
It was pars all the way from there on his way to 75.
McIlroy though, who has won the tournament twice, was right in the hunt and said Quail Hollow is one of his favourite courses and that he has "always had a great affinity for this place".
He said following his round: "Playing in front of these fans, I feel like Charlotte has sort of taken me in as one of their own. It’s been a great journey. I’ve celebrated I think 13 of my last 15 birthdays here as well because obviously when the tournament falls.
"Some awesome memories, and obviously trying to keep making more of those."
Meanwhile, American Schauffele hit a seven under par 64 with six birdies and an eagle on the seventh hole while only dropping one shot.
Additional reporting: PA
