Rory McIlroy fired seven birdies to share the clubhouse lead with six others at the Wells Fargo Championship at Quail Hollow.
The world number two, whose first PGA Tour win came at the North Carolina venue in 2010, fired a five-under 67 to match Americans Ryan Moore, Nick Watney, Robert Garrigus, Derek Ernst, Daniel Summerhays and Nate Smith.
McIlroy, also a runner-up on this course last year, made a steady start but then reeled off four straight birdies at five, six, seven and eight. A bogey at nine saw him turn in 33 but further gains at 10 and 11 took him into a tie for the lead at five-under and suggested he might kick clear of the field.
However, a bogey at 12 and two missed birdie opportunities at 14 and 15 halted his momentum although he did round the day off with another birdie at the last following an excellent approach to inside 10 feet.
"I was hitting some good shots in there and leaving the ball quite close to the pins which you need to do out here. It's hard to hole long putts," said McIlroy, a reference to the poorly conditioned greens which have been a big issue in the build-up to the tournament.
"I played well, I gave myself plenty of chances and I'm really happy with today," said the Ulsterman, who hit 15 greens in regulation.
Phil Mickelson - like McIlroy, playing for the first time since The Masters - also started brightly after posting a four-under 68.
Lee Westwood is also handily placed after a 70 but Padraig Harrington finished the day dead last after shooting an eight-over 80.
Harrington was using a belly putter for the first time although it was his long game which let him down in a round which included nine bogeys.