Colombian Sebastian Munoz stretched his overnight lead to three shots after the second round of the Greenbrier Classic in West Virginia.
Munoz followed up his opening 61 with a three-under-par 67 to be 12-under halfway through the PGA Tour event on the Old White TPC in White Sulphur Springs.
Ben Martin (67) and Hudson Swafford (66) moved into a share of second on nine-under.
After a first-round 63, 21-times PGA Tour winner Davis Love III posted a 69 to fall four strokes off the pace, where he was joined by Russell Henley (64) and New Zealand's Danny Lee (68), the defending champion.
Matt Jones was the best of the Australians at four under and in a tie for 22nd after an even-par 70 in his second round.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
After a late finish on Thursday, Munoz made another strong start with four birdies in his first seven holes in ideal morning conditions.
Though he could not quite maintain his run, he had no complaints about his position, and eight-foot par-save at the last further buoying his spirits.
"It's fantastic," he told reporters. "No regrets. Excited."
Munoz hopes to benefit from the experience of sharing the halfway lead four weeks ago in Memphis, where he plunged over the weekend to finish equal 60th after playing the final 36 holes in 11-over.
"I feel like Memphis taught me that maybe I was caring too much, trying to hit too many perfect shots all the time," said the PGA Tour rookie.
Lee, meanwhile, bounced back from a double-bogey at the par-five 12th, his third hole, and stayed in the hunt to successfully defend his title after a two-year wait after floods forced the event to be cancelled last year.
Lee said the course really suited his game.
"I love hitting three woods off the tee and some of the courses it's too long to do that, but this course it just sets up perfect for a lot of those," he added.
