Washington - Jordan Spieth birdied three of the last four holes, including the last with a dramatic 20-foot putt, to grab a one-stroke lead after Saturday's third round of the PGA Tour's Travelers Championship.
Sixth-ranked Spieth, the 2015 Masters and US Open champion, shook off back-to-back bogeys at 13 and 14 with a sizzling finish, curling in his final putt for a four-under par 66 to reach 12-under 198 after 54 holes.
The 23-year-old American, who won earlier this year at Pebble Beach, could complete a wire-to-wire triumph and claim his 10th PGA title Sunday at TPC River Highlands near Hartford, Connecticut.
American Boo Weekley, who hasn't won a PGA title since 2013 at Colonial and hasn't finished in the top 25 this season, fired a 65 to stand second on 199 with compatriot Daniel Berger third on 201.
Taiwan's C.T. Pan fired the day's low round, a 64, to join England's Paul Casey and Sweden's David Lingmerth in fourth on 202.
Spieth hopes to carry the momentum from his strong finish into the final round on Sunday.
"I'm going to go out there and play solid golf," Spieth said. "That's what we've been doing. That's cliche, but a couple (birdies) a side on a round like today, I thought at the beginning of the week if you shot 4 under each day, you'd be right there. So I think that's the goal."
Spieth began the day with a one-stroke edge and five opening pars solidified his spot. He found a bunker at the par-3 fifth but sank a clutch 15-foot par putt to stay ahead.
Spieth followed with birdies at the par-5 sixth and par-4 seventh. He blasted from a bunker to off the edge of the green then sank the birdie bid from 27 feet, then landed his approach inside three feet and sank the birdie putt to reach 10-under.
But Spieth closed the front nine with a bogey for the second time in three days and seconds later Charley Hoffman completed an eagle-birdie-birdie run by sinking a five-foot birdie putt at 15 to seize the lead by one at 10-under.
Spieth responded with birdies from eight feet at the 10th and half that distance at the par-3 11th to reach 11-under, jumping back in front as Hoffman made double bogey at the par-3 16th and closed bogey-bogey.
A splashdown second shot for Spieth at the par-5 13th led to a bogey, trimming his edge to one stroke over Daniel Berger.
But Spieth missed the green on his approach at 14 and missed a six-foot par putt to fall into a share of the lead with Berger and Weekley.
Again Spieth answered the challenge, firing his tee shot at the par-4 15th into a greenside bunker, then blasting out inches from the cup for a tap-in birdie to reclaim sole possession of the lead at 10-under.
Spieth then sank a five-foot birdie putt at the par-3 16th to share the lead with Weekley at 11-under after his rival's birdie-birdie finish, setting up his dramatic go-ahead birdie at 18.
Third-ranked Rory McIlroy, who made the cut on the number, switched to a half-mallet putter as he searched for better results on the greens. He shot 70 with two birdies and two bogeys to stand on 210.
Leading scores after Saturday's third round of the PGA Tour Travelers Championship (Par 70; USA unless noted):
198 - Jordan Spieth 63-69-66
199 - Boo Weekley 66-68-65
201 - Daniel Berger 68-67-66
202 - C.T. Pan (TPE) 70-68-64, David Lingmerth (SWE) 67-70-65, Paul Casey (ENG) 68-68-66
203 - David Hearn (CAN) 67-70-66, Keegan Bradley 67-70-66, Danny Lee (NZL) 68-67-68
204 - Jason Kokrak 71-67-66, Webb Simpson 70-68-66, Charley Hoffman 69-67-68, Chez Reavie 69-66-69, Patrick Rodgers 70-65-69
205 - Marc Leishman (AUS) 69-68-68, Bryson DeChambeau 67-72-66, Brian Harman 66-70-69, Ryan Brehm 68-68-69, Brendan Steele 68-68-69, Patrick Reed 67-66-72
206 - Rick Lamb 69-69-68, Morgan Hoffmann 67-70-69, Xander Schauffle 66-70-70, Padraig Harrington (IRL) 66-69-71, Bryce Molder 70-70-66, Chase Seiffert 68-66-72, Troy Merritt 65-68-73