Seven strokes ahead of the chasing pack overnight in pursuit of his fifth PGA Tour victory of the season, Woods carded a two-under-par 68 on a warm, breezy day at Firestone Country Club.
The American world number one, winner of a record seven titles here, struggled at times for accuracy off the tee as he mixed five birdies with three bogeys for a 15-under total of 195.
Woods had distanced himself from the field with a stunning 61 on Friday and will head into Sunday's final round with an intimidating record, having triumphed 52 of 56 times on the PGA Tour when holding at least a share of the 54-hole lead.
His closest challenger is Swede Henrik Stenson, who fired a 67 to leave him at eight under.
Jason Dufner, who birdied his first four holes on the way to a matching 67, was alone in third at seven under, a stroke better than fellow American Bill Haas (69) and Englishmen Luke Donald (68) and Chris Wood (70).
British Open champion Phil Mickelson, who by his own admission struggled for focus in his opening round, carded a 67 to finish at even-par 210, level with U.S. Open winner Justin Rose and world number three Rory McIlroy (69).
(Reporting by Mark Lamport-Stokes; Editing by Steve Keating)
