Two-time major winner Zach Johnson rolled in a five-foot birdie putt at the 18th on Thursday to seize a share of the first-round lead at the US PGA Tour Sony Open in Hawaii.

Johnson, the 2009 winner at Waialae in Honolulu, had seven birdies in his seven-under 63, joining early pace-setter Chris Kirk atop the leaderboard in the US PGA Tour's first full-field event of 2018.

Kirk, a four-time winner on the US tour, nabbed five of his seven birdies on the back nine. He had a look at eagle on the par-five 18th, where he holed a two-footer for birdie.

Johnson got off to a hot start in his pursuit of Kirk, with birdies at the first three holes. He added another birdie at the ninth, and after a near-miss at the 12th rolled in birdie putts of 24 feet and 21 feet at 13 and 14 to move within a stroke of the lead.

Johnson, winner of the 2007 Masters and the 2015 Open championship, broke away from the second-placed bunch at the final hole, despite finding a fairway bunker off the tee.

Johnson admitted his round was a pleasant surprise, after a bout of flu cost him some pre-season practice time.

"I came here later than I anticipated -- like four or five days later and I had zero expectations on my game," the 41-year-old said.

"That being said, sometimes it's nice, you just kind of go out there, find a rhythm and then just stick with it."

Kirk, whose most recent victory was at Colonial in 2015, said a return to his old putting routines had paid off on the greens.

"I'm kind of going back to some of the drills that I did four, five years ago when I was putting week-in, week-out really well, and trying to do those drills every day," Kirk said.

"I had a great day today, and I'm about to go do it. It takes about five or 10 minutes. It's laziness, I guess, not doing it consistently over the last couple of years."

The leading duo were one stroke in front of a group of four players on a crowded leaderboard.

Vaughn Taylor fired six birdies in his six-under 64 and was tied with Brian Harman, Kyle Stanley and Talor Gooch. Stanley capped his round with an eagle at the par-five ninth, rolling in a 41-footer.

Gooch rocketed out of the blocks with three straight birdies, finishing with eight birdies overall against two bogeys. Harman, playing in the afternoon, had eight birdies that included three in a row at the fifth, sixth and seventh.

Japan's Daisuke Kataoka and Americans Peter Malnati, Matt Every and Tom Hoge all shot 65.

- Spieth's quadruple misery -

World number two Jordan Spieth dropped back late with a quadruple-bogey eight at his penultimate hole -- the par-four eighth.

Spieth was rolling at four-under when he fired into a tree off the tee at eight. His next three shots also hit trees before he found a greenside bunker.

He rallied somewhat with a birdie at his final hole for a one-under par 69.

Defending champion Justin Thomas, who fired a first-round 59 in route to victory last year, had three birdies in a three-under 67.

World number four Thomas had Phil Mickelson's former caddie Jim "Bones" McKay on his bag, filling in for regular caddie Jimmy Johnson, who is sidelined by plantar fasciitis.