US Open champion Webb Simpson withstood an unexpected charge by journeyman Troy Kelly to move two strokes clear after Saturday's third round of the weather-hit Greenbrier Classic at White Sulphur Springs in West Virginia.
Seeking his fourth PGA Tour title, Simpson coolly birdied four of the last six holes for a five-under-par 65 on the Old White TPC Course to post a 14-under total of 196.
Simpson rolling in a 20-footer on the 18th green to finish two ahead of fellow American Kelly who rocketed up the leaderboard with a flawless eight-birdie 62.
Long-hitting American JB Holmes carded a 66 to share third place at 11 under with compatriots Ken Duke (65) and PGA Tour rookie Charlie Beljan (67).
Overnight leader Simpson remained a stroke ahead of the chasing pack when the weather-delayed second round was completed earlier on Saturday but he slipped one behind Kelly after recording a lone birdie on his front nine.
Kelly, who had raced to the turn in a scintillating five-under 29 before picking up his sixth shot of the day at the 12th, went on to birdie 16 and 17 to forge two ahead.
The 33-year-old, a lowly 464th in the world rankings, narrowly missed a long-range birdie attempt at the par-three last but set the clubhouse lead at 12 under before being caught by Simpson who birdied 13 and 14.
The 26-year-old then regained overall control, getting up and down from a greenside bunker to birdie the par-five 17th before draining the 20-footer at the last.
