(REUTERS) - Former teenage golf prodigy An Byeong-hun seized the sole halfway lead at the Wyndham Championship in North Carolina on Friday (Aug 2), as big guns Webb Simpson, Jordan Spieth and Paul Casey focused their sights for a weekend shoot-out.
The South Korean remained bogey-free for the tournament as he carded a tidy five-under 65 in the second round on a languid afternoon at Sedgefield Country Club in Greensboro.
"It was an 'okay' day," the 27-year-old said after signing for a 13-under 127 score.
An headed American Brice Garnett (64) by one stroke with a group of six, including 2011 champion Simpson (65) and Canadian Adam Svensson, two shots off the lead.
Svensson's 61 was the best score of the day by three shots, and he reacted incredulously when asked by a reporter when had been the last time he had broken 60.
"Sixty? Never done it," he said.
Casey shot a 65 to stand three shots off the pace and another superb day on the greens left Spieth (67) four behind, well within striking distance for the weekend.
Leader An became the youngest US amateur champion when he won the prestigious title in 2009, but a decade later is still seeking his PGA Tour breakthrough.
The quality of his putting does not always match his tee-to-green game, but he found his range on the greens on Friday and rolled in a couple of long ones to complement a few tap-ins.
"It was a bit shaky today. I didn't hit it as good as yesterday, but I grinded it out," he said.
"A lot of golf to do, so just do what I've been doing the last couple days and hit a lot of fairways and greens and make some putts.
"If someone plays better than me, then he deserves to win it, but as long as I keep these bogey-free rounds going."
Lurking equal 12th at 131, Spieth is still mixing some fine play with the occasional poor swing, and he found a ready scapegoat for a wayward second shot at the par-five 15th that ended up out-of-bounds.
"The cart paths are just so inconveniently placed. I almost think of them as the out-of-bounds markers," said the three-time Major winner.
"If it stays in play, I think I look at the round a little bit differently than just average."
Playing companion Casey was certainly impressed with Spieth's putting.
"Jordan was making the hole look like a bucket," said the Englishman, who predicts a winning score of at least 20 under.
"I'm happy with another 65," he said. "Can I get two more of those?"