NEW YORK (AFP) — World number one Scottie Scheffler fired an eagle and seven birdies in an eight-under-par 62 to seize a share of the first-round lead alongside Austin Eckroat in the US PGA Tour Travelers Championship in Connecticut on Thursday.

After six birdies in the first 12 holes, Scheffler tied Eckroat on eight-under with a 10-foot eagle putt at the par-five 13th.

He landed his second shot from the left rough within five feet at the par-four 15th and made that for birdie and the solo lead, and even after a bogey at the 17th the US star was pleased with a round played in tougher afternoon conditions.

“I did a lot of good stuff,” Scheffler said. “I felt like the conditions were pretty challenging out there, especially late in the day. I was able to hole some nice putts as well.”

Scheffler set up his eagle at 13 with a “really nice” three-iron.

“Very rarely throughout a tournament do you hit one exactly how I intend to, and that was one of the few,” Scheffler said.

The leading pair were two shots clear of a trio headlined by world number two Rory McIlroy.

McIlroy, coming off a disappointing US Open run last week, had six birdies without a bogey and was joined on six-under by major winners Keegan Bradley and Wyndham Clark on 64.

McIlroy said the more forgiving TPC River Highlands layout was “a nice tonic” after the brutal US Open setup at Oakmont, but said his focus was not so much on winning but on his game.

“I just want to see some good golf and see some better shots,” said McIlroy, who completed his career Grand Slam with a victory at the Masters in April.

“I think if you concentrate on that and you’re concentrating on your quality of golf and concentrating on just trying to play to the best of your ability, the result will take care of itself.”

Eckroat had set an early target with his career-low score on the PGA Tour, crediting an adjustment to his grip with sorting out a tendency to miss left that has contributed to eight missed cuts this season.

Spieth withdraws

“It’s funny,” Eckroat said, “a lot of Wednesdays I’ve felt really good going into the tournament and then Thursday comes around and it hasn’t been there.

“I don’t know if it’s just the stress of playing in a PGA Tour event, but this one, it was nice to feel good on Wednesday and then actually take it into Thursday.”

Eckroat, a two-time winner on the tour, got off to a solid start with three birdies on the front nine then stormed home. He drilled a 35-foot eagle putt at the 13th, then birdied 14, 15 and 18.

Three-time major winner Jordan Spieth was forced to withdraw from the elite signature event after 13 holes as pain in his upper back and neck affected his swing.

Spieth said the injury came on suddenly on Thursday morning and he hoped to play through it, but he was five-over for his round when he decided to call it quits -- the first time he has withdrawn from a PGA Tour event in 297 career starts.

“It just became too much,” Spieth said.

US Open champion J.J. Spaun got off to a rocky start in the wake of his first major title, carding a three-over-par 73.

The leading scores:

62 — Austin Eckroat, Scottie Scheffler

64 — Wyndham Clark, Rory McIlroy (NIR), Keegan Bradley

65 — Cameron Young

66 — Davis Riley, Nick Taylor (CAN), Jason Day (AUS), Adam Hadwin (CAN), Max Greyserman, Tommy Fleetwood (ENG), Viktor Hovland (NOR), Brian Harman.