Defending champion Rory McIlroy delivered an improved performance on the second day of the Wells Fargo Championship in Charlotte as he finished six shots off the lead.
McIlroy, looking for his third triumph at Quail Hollow, started Friday eight shots off the top having shot a first-round 73.
The world number three went on to cut the gap to American leader Andrew Loupe with a three under par 69.
The Northern Irishman was in even better shape after 16 holes, having registered five birdies, plus a chipped-in eagle on the seventh.
But the 27-year-old then endured a frustrating finish as he posted his third and fourth bogeys of the round.
Loupe, who led alongside fellow American Steve Wheatcroft after an opening round 65, followed up with a 71 which put him on his own on eight under, a shot clear of Roberto Castro.
Chesson Hadley and Mark Hubbard were a shot further adrift, while Phil Mickelson moved into contention with a round of 70. He was among six Americans on five under par, with Wheatcroft one of them.
Mickelson produced a 15-foot putt for a birdie on the 18th, a hole which has not been kind to him in the past despite eight top-10 finishes - one of which came in 2010, when he was runner-up to McIlroy.
In quotes reported by the Golf Channel the left-hander said: "It's a very awkward shot for me off the tee because if I happen to lose it a little bit left, obviously it's going to go in the water.
"But these last two days I've just played up the right-hand side, and I'll take that every day on 18."
Justin Rose was the best placed European on four under par after a second successive round of 70, with fellow Englishman Paul Casey a shot further back after a second round 71.
Ian Poulter slipped out of contention with a 74 which left him sharing 45th place on level par, while Luke Donald moved up to one over after a second round 69. Scotland's Martin Laird was alongside him in a share of 62nd but heading in the other direction after a 76.
Two over was not enough for Greg Owen, while Ireland's Shane Lowry also failed to make the cut after finishing a shot further back. Also missing out were Wales' Jamie Donaldson (five over par) and Padraig Harrington (seven over par).
Meanwhile, American Zac Blair was disqualified for using a non-conforming club after bending his putter when he hit himself in the head with it having missed a putt for birdie.
The 25-year-old tweeted afterwards, with the hashtag GottaDoBetter: "I let my emotions get the best of me today...going forward I'm going to do my best to not let my emotions get in the way out on the golf course, and I'm going to learn from this mishap and move on."