Hartford - Jordan Spieth posted the lowest opening-round score of his career on Thursday with a 63 at the Travelers Championship.
The 23-year-old Spieth, who is coming off a disappointing tie for 35th at the US Open, made his eighth birdie of the round on his last hole to seize a one-shot lead in his first career appearance at the PGA Tour's Travelers Championship.
Rory McIlroy, who is also playing in the event for the first time, shot a 67 after missing the cut last week at the US Open.
Tied for second were Johnson Wagner and Brett Stegmaier after posting 64s in the morning. Spieth played in the afternoon at par-70, 6 841-yard River Highlands course.
Spieth, who has finished in the top 10 six times in 15 events this year, hit eight of 14 fairways in regulation and 15 of 18 greens while needing 27 putts.
Two-time major winner Spieth built on the momentum from his final-round 69 at the US Open, rolling in a 15-foot birdie putt on the first hole on Thursday.
"That one going in on the first was big for me," Spieth said. "And then I made one on the fourth that was a putt that required a lot of precision, kind of a right-edge putt.
"When that one went in is when I really started to feel good with the putter."
Stegmaier, a Connecticut native who has missed the cut in eight of his last 10 tournaments, reeled off seven birdies in a nine-hole stretch through the middle of the opening round.
His lone blemish was a bogey at number nine, his final hole of the day, as he matched his low round on the PGA Tour.
Wagner got off to a hot start, holing out a 69-foot chip from off the first green. Wagner entered the tournament having missed the cut in his last five starts. The last of his four career wins came at the 2012 Sony Open in Hawaii.
"It was a nice way to start and kind of let me know today was going to be my day," he said.
Graham DeLaet of Canada and Troy Merritt opened with 65s. DeLaet's round included an eagle-three at the sixth hole.
World number three McIlroy missed several short birdie putts but managed to scramble for par on most of those holes.
"I feel like I could have been at least three or four better," said McIlroy. "I think I hit five or six putts out there that hit the hole and didn't go in."
Jim Furyk, who shot a 12-under 58 last year in the final round of the tournament, settled for a 67.
Former world number one Jason Day, of Australia, struggled to a 72.
Leading scores after the first round Thursday in the PGA Tour Travelers Championship (Par 70; USA unless noted):
63 - Jordan Spieth
64 - Johnson Wagner, Brett Stegmaier
65 - Graham DeLaet (CAN), Troy Merritt
66 - Xander Schauffele, Fabian Gomez (ARG), Hudson Swafford, Padraig Harrington (IRL), Brian Harman, Boo Weekley, Tom Hoge, Matt Every, Scott Piercy, Mark Hubbard, Kevin Na, Daniel Summerhays, Beau Hossler