By Andrew Both
GREENSBORO, N.C., Aug 3 (Reuters) - An Byeong-hun stayed ahead in his quest for a breakthrough PGA Tour victory on Saturday, remaining bogey-free for the tournament with a four-under-par 66 in the third round at the Wyndham Championship.
The South Korean, joint leader in the first round and alone in front overnight, will start the final round on 17-under, one stroke ahead of Americans Webb Simpson (65) and Brice Garnett (66) at Sedgefield Country Club.
On a packed leaderboard, American Ryan Armour (65) is two shots off the lead, while Englishman Paul Casey (66), American J.T. Poston (66) and Norway's Viktor Hovland (64) trail by three.
An, who has finished runner-up three times on the PGA Tour, but is still seeking his first victory at the age of 27, has downplayed his form all week and Saturday was no different.
"One shot is basically nothing," An said.
"Sixty-six is a decent score here when you have the lead. Still, I'm only one ahead of everyone, so I just need to keep my head straight and try to play my best golf tomorrow.
"I hit some good shots today, not as good as the first round, but still I'm quite happy with where I am and I'm holing a lot of putts."
He will play the final round with local favourite Simpson, who lives in nearby Charlotte and recorded his first tour victory here in 2011.
While Simpson has since claimed bigger titles, including the 2012 U.S. Open, this tournament holds a special place in his heart.
The world number 17 awarded himself an "A minus" for his round.
"There's a lot of reasons I want to win but I've got a lot of work to do, especially with how many guys are within a few of the lead," he said.
"I've got to keep the pedal down and if I don't shoot a low one, I'm not going to win."
Englishman Casey echoed Simpson's thoughts and said he had revised his initial assessment of what it would take to win.
"At the start of the week I had 20 (under par) in my mind but I don't think it's gong to be low enough," said the former world number three.
Casey had a frustrating day with the putter.
"I had two three-putts," he lamented.
Hovland, making only his fifth start as a pro, jumped into contention by matching the day's low score.
The 21-year-old piled up five birdies in an outward half of 30, but could not continue at such a blistering pace as the putter cooled off.
"After that start I felt there's something special out there today," he said.
Three-times major champion Jordan Spieth had the day's worst score -- a 77 that included three double-bogeys -- and missed the cut. (Reporting by Andrew Both, editing)