South Korean Kim Si-woo birdied the final hole as he turned a narrow advantage into a four-shot lead after the third round at the Wyndham Championship on Saturday.
Kim was almost flawless, carding a six-under-par 64 to move within sight of his first PGA Tour victory.
He began the day with a two-shot cushion after a second-round 60, birdied the first two holes and hardly put a foot wrong.
The 21-year-old from Seoul put an exclamation mark on his day by stiffing his approach shot to three feet for a birdie at the last as he posted an 18-under 192 total.
"I feel very good now. My shots much more consistent," Kim said.
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Spaniard Rafa Cabrera-Bello shot 65 to jump into second place on 14-under, a shot ahead of Americans Jim Furyk and Kevin Na and Briton Luke Donald on 13-under.
Journeyman Cameron Percy was the leading Australian, tied 18th and nine shots from the lead after following his second round 64 with a 66, while Rhein Gibson (67), Greg Chalmers (69) and Geoff Ogilvy (68) were tied 41st at six under.
Na shared the lead after 11 holes and was two strokes behind going to the last, only to finish with a double bogey.
But Kim cannot plan his victory speech just yet, with so many quality players within striking distance.
Cabrera-Bello, coming off a tie for fifth at the Olympics last week, continued his strong form and is confident about his chances of a strong finish.
"There is damage to be done," he said of the course.
"The greens are brilliant. Give yourself chances and you will roll putts and that's what I'm going to try to do tomorrow."
And Furyk cannot be discounted, despite bogeying the final two holes.
"I got off to a slow start and stayed real patient today. I was proud of that," said Furyk, who sank a 60-foot monster putt to eagle the par-five 15th.
