Northern Ireland's Rory McIlroy shot a 5-under-par round of 66 on Thursday to share the first-round lead with Joel Dahmen at the Wells Fargo Championship in Charlotte, N.C.

After shooting even par on the front nine, McIlroy blistered the back side of the Quail Hollow Club in 5-under 31 thanks to five birdies over a seven-hole stretch. He was the first to get into the clubhouse at 5 under, with Dahmen birdieing the 18th hole several groups later to match McIlroy.

McIlroy earned his first career PGA Tour victory at Quail Hollow in 2010, and is the only two-time winner of the event. However, there is still a stacked leaderboard behind him.

"(The golf course) went through different iterations since we started coming here, but every time they tweak something here or there, you know, it's still sort of the same place and it really fits my eye," McIlroy said, according to "I think it's the purest golf course we play all year in terms of preparation and how manicured it is.

"It just has a really nice feel about it. I've always felt comfortable here. I've obviously got good memories."

Five players only one shot off the pace include 2018 Masters champion Patrick Reed, Adam Schenk, Scotland's Marin Laird, Canada's Nick Taylor and South Africa's Dylan Frittelli. Another shot back at 3 under is Australia's Jason Day, who is attempting to defend a title on the PGA Tour for the first time. He had five birdies against two bogeys in posting 68.

"It was good today," Day told reporters after the round. "You had to be careful with that wind today, because it is moving around a little bit, but overall very pleased with the opening."

Day was paired with Phil Mickelson, who is tied for 47th after an even-par round of 71, same as previous event champion Rickie Fowler. After carding a pair of birdies and bogeys through the first eight holes while starting on the back nine, Mickelson reeled off 10 consecutive pars to close his round.

"My game feels a lot better than my score today," Mickelson said. "It was kind of a lethargic, lazy, unexciting round. Hit a lot of greens and didn't make any putts. I came in here fresh, and I think the next three days it's going to get better."

Webb Simpson, whose home is located on the course, is within striking distance at 2 under and said being at his home course no longer presents distractions in trying to compete.

"This week has been pretty laid back. We did all of our busy stuff already," he told the Golf Channel. "Saw a lot of people early in the week, but now it's time to focus on golf. I feel like I've learned how to just enjoy it and use it to my advantage."

NOTES: Tiger Woods, the 2008 event winner, is not in the field and is not expected to play until the PGA Championship in two weeks. ... McIlroy will turn 30 on Saturday and has seven top-10 finishes in nine starts this year. ... The Wells Fargo Championship is one of seven Tour events Mickelson has played at least 15 times without posting a victory.