(CNN) -- Two-time major winner Rory McIlroy showed glimpses of the form which shot him to the top of the world rankings by hitting a five-under-par round of 67 to share the lead after the opening round of the Wells Fargo Open.
McIlroy, who has struggled to produce his best golf since signing with Nike in January, shares the top of the leaderboard with six American players.
"I felt like I played really well," the world No. 2 told the PGA Tour's official website after a round which included seven birdies and two bogeys.
"I feel a lot more comfortable with my swing and a lot more comfortable with where my game is at. That's always going to make it easier."
McIlroy won this event in 2010 and is playing for the first time since tying for 25th at the Masters in April.
"I love this golf course," added the 23-year-old, referring to the Quail Hallow Club in Charlotte, North Carolina. "I always seem to play well here, so that's an added benefit.
"I took the best part of two weeks off after Augusta and didn't touch a club. Flew back out to Florida last Friday, had three or four really good days' practice, and I feel good about my game.
"I knew if I could just take that from there to here, I'd do OK."
Alongside McIlroy are the six Americans Ryan Moore, Nick Watney, Robert Garrigus, Derek Ernst, Daniel Summerhays and Nate Smith.
Four-time major winner Phil Mickelson and 2007 Masters winner Zach Johnson are part of a six-strong group one stroke further back on four under.
"I really like this golf course," said Mickelson, who is looking for a first career win at this event. "I think from tee to green it's one of the best I've ever seen. I really enjoy playing here.
"I've had some good finishes, but you're right. I haven't been able to break through and get a win. This year, hopefully, it will be different because I am playing well and I do really enjoy it here."