Robert Streb fired a seven under 65 to hold a one-shot lead at the Wells Fargo Championship, with world No 1 Rory McIlroy in contention five strokes back.
McIlroy, who won his maiden PGA Tour title at Quail Hollow, struck six birdies during a solid first round and had been within three strokes of Streb heading to the penultimate hole, but slipped down the leaderboard after sending his tee-shot at the par-three 17th in to the hazard and running up a double-bogey.
Streb had set the early pace by opening with back-to-back gains in a blemish-free round and added five further birdies, including a 30-foot putt at the 17th, to remain one stroke clear of Patrick Reed and Kevin Chappell.
Reed had held a share of the lead until a two-putt bogey at the 17th after finding the bunker off the tee, while Chappell picked up three strokes in the space of two holes on the Green Mile late in the day to close with a first round 66.
Veteran Stewart Cink raced through the field with the aid of three successive birdies around the turn as he finished part of the group five under, while Webb Simpson is handily placed on his home course after shooting 67.
Simpson is a member at Quail Hollow Club, with the former US Open champion making six birdies on his way to a sub-70 first round at the tournament for the fifth year running.
"It was a good, solid day. I didn't make many mistakes," Simpson told Sky Sports 4. "The one that cost me was 16. I just went through it wrong mentally and hit it in the water. Other than that, the card was clean and I played nicely."
Ireland’s Padraig Harrington finished tied-30th alongside McIlroy, while Russell Knox was a stroke further up the leaderboard alongside defending champion JB Holmes following a bogey-free 69.
"It was a strange day for me," Harrington told Sky Sports 4. "Last week I played really well and putted terrible, but I putted unbelievable today and didn’t play so well."
Phil Mickelson could only card a first round 71 despite kicking off his round with three successive birdies, while Henrik Stenson and Jim Furyk sit a further stroke back.
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