Rickie Fowler carded a flawless third round of 68 to take the outright lead at the top of The Barclays standings heading into the final day.
The 27-year-old remained bogey free once again to keep alive his hopes of booking a place in the Ryder Cup, ousting Patrick Reed at the summit after the American saw his advantage slip away.
Fowler finds himself on nine-under-par at the Bethpage Black course in New York, a shot ahead of compatriot Reed and two ahead of former world number one Adam Scott who is still in contention in third place.
The top eight on Sunday evening will secure a place in the US team to face Europe in the Ryder Cup next month, with Fowler well on course for a third appearance in the famous competition.
Scotland's Martin Laird is further back on six-under, meanwhile, level with Emiliano Grillo heading into Sunday's final session on the notoriously difficult course.
