An Byeong-hun edged into a one-stroke lead at the Wyndham Championship, while Jordan Spieth remained in contention at the halfway mark.

An, 27, sits alone atop the leaderboard at 13 under entering the weekend at the Sedgefield Country Club in Greensboro, North Carolina.

The South Korean shot a blemish-free five-under 65 on Friday with consecutive birdies on his front nine, the 14th and 15th holes, and again after he made the turn from the third through the fifth.

His steady play kept him ahead after entering the day sharing the 18-hole lead, and all it took was some impressive putting to separate himself from the field. An sunk a 30-foot putt at the fourth hole and sits just one stroke ahead of Brice Garnett.

Garnett matched his opening round of six-under 64 to move into second at 12 under.

He also finished the day with a clean scorecard and was mere inches away from yet another tie for first.

Spieth backed up his opening-round 64 with a three-under 67 to get to nine under, four shots adrift of the lead.

Im Sung-jae – the other 18-hole leader – Patton Kizzire, Adam Svensson, Josh Teater, Webb Simpson and Mackenzie Hughes are at 11 under.

Paul Casey highlights the three-way tie for ninth at 10 under, while defending champion Brandt Snedeker fell back to a tie for 38th after an even-par 70.

Hideki Matsuyama, Jimmy Walker, Kevin Streelman and Cameron Smith missed the cut, set at four under.