Defending champion Patrick Cantlay will take a one-stroke lead into last round of the BMW Championship, the second event of the FedEx Cup play-offs.
The American world number four, 30, started the day two shots behind halfway leader Adam Scott of Australia.
But he holed a 43-foot birdie putt at the first and picked up five more shots and made one eagle in a 65.
The six-under round at Wilmington in Delaware leaves him one clear of Xander Schauffele and Scott Stallings.
Schauffele’s bogey-free third round included an eagle, three birdies and 14 pars while fellow American Stallings carded a 66 that featured six birdies.
Scott – the only non-American in the top seven – is a shot further back on 10 under alongside world number one Scottie Scheffler after a two-under 69 that included four birdies and two bogeys.
Northern Ireland’s Rory McIlroy failed to keep pace with the leaders and is five shots behind Cantlay following a 70.
