Adam Long fired an eight-under-par 64 to open up a two-shot lead at the PGA Tour Corales Puntacana Championship on Saturday.
The 33-year-old American carded eight birdies and 10 pars in a flawless bogey-free round at the Corales Puntacana resort in the Dominican Republic.
Long, who is chasing only his second career PGA Tour title after victory at the Desert Classic last year, had started the third round three off the lead.
But Long began moving up the leaderboard after reeling off four birdies over the front nine to reach the turn at four under, 13 under overall.
A brilliant second shot from the fairway on the par-four 10th left him with a three-footer for his fifth birdie of the day which he duly converted.
Long then went on a run of three consecutive birdies on the 12th, 13th and 14th holes to move two shots clear of the pack on 17 under overall.
Second round leader Hudson Swafford will lead the pursuit of Long in Sunday's final round after a battling three-under-par 69.
Swafford had started his second round with a wobble, bogeying the par-three second to drop a shot.
But he regained his momentum on the fourth with a birdie, and then rolled in a 20-foot putt for eagle on the par-five seventh.
Another birdie on the eighth took Swafford to 15 under but his momentum faltered thereafter, finishing his round with 10 consecutive pars to end the day in second place on 15 under.
Canada's Mackenzie Hughes is alone in third place on 14 under after a five-under-par 67.
Hughes opened with a bogey but then climbed the leaderboard on the back nine with three consecutive birdies, chipping in from off the green on both the 15th and 17th holes.
China's Zhang Xinjun is four off the lead on 13 under after a four-under-par 68, one ahead of Nate Lashley and Sean O'Hair, who are tied for fifth on 12 under.
The biggest move on Saturday came from India's Anirban Lahiri. The 33-year-old from Pune jumped 47 places up the leaderboard with an eight-under-par 64.
Lahiri's bogey-free display was capped by his eighth birdie of the day on the 18th green, leaving him tied for seventh place on 11 under alongside Americans Tyler McCumber, Luke List and Justin Suh.