Nick Watney produced a stunning eight-under-par 64 to snatch a one-stroke lead at the halfway stage of the Wells Fargo Championship at Quail Hollow.
The world No.25, without a top-10 finish in a PGA Tour stroke play event for over seven months, carded seven birdies and an eagle to edge ahead of fellow American Webb Simpson after 36 holes in South Carolina.
Watney found 17 greens in regulation en route to posting his lowest round of the season so far.
The resident of Las Vegas, who arrived at Charlotte in mediocre form, admitted after Friday's excellent round: "I think last week missing the cut was a wake-up call for me.
"I've worked really hard these five days leading into this event. I think it just shows I'm making progress.
"Who knows what's going to happen this weekend but I'm really excited for it. More hard work and hopefully I'll be in this position a lot more."
Simpson had started the day in a three-way share of the lead with Stewart Cink and Ryan Moore.
However Cink dropped to a share of third with Moore down in seventh.
Americans dominate the leaderboard, though, and hold eight of the top nine spots while the leading Europeans are Rory McIlroy and Robert Karlsson who are six strokes of the pace.
McIlroy, winner of this event two years ago, carded a second round 68 that yielded five birdies and a single bogey.
Lee Westwood and Phil Mickelson both recorded 72s to edge their way into the weekend on one under, however Tiger Woods failed to make the cut by one shot.
Defending champion Lucas Glover also bowed out with a round of 76 ending his challenge.