William McGirt and Mackenzie Hughes upstaged a star-studded Players Championship field to earn a share of the lead after the opening round.

All eyes were on world number one Dustin Johnson, defending champion Jason Day and two-time major winner Jordan Spieth at TPC Sawgrass on Thursday.

But McGirt and Hughes – with one PGA Tour title apiece – set the early pace via five-under-par 67s to be a stroke clear in Ponte Vedra Beach, Florida.

McGirt's flawless front nine, which yielded three birdies, inspired the American as he eagled the 11th and 16th holes in between bogeys at the 10th and the 18th.

It was another fast start for McGirt, who opened the Masters with a 69 to be second after the opening round before ultimately finishing tied for 22nd.

Canadian Hughes was flawless in his round, having played 18 holes without posting a bogey.

Hughes birdied his opening hole and gained strokes at the ninth, 10th, 13th and 16th.

J.B. Holmes, Alex Noren, Chez Reavie and Jon Rahm are a shot off the pace heading into Friday's second round.

There are 11 players at three under, including Francesco Molinari, Louis Oosthuizen, Brendan Steele and Kyle Stanley.

Former world number one Day's title defence got underway with a two-under-par 70.

Teeing off from the back nine, Day was bogey-free with three birdies but the Australia star faltered late.

After back-to-back birdies following the turn, Day ended his round with three bogeys from his last four holes.

Rickie Fowler and Adam Scott are also three shots behind McGirt and Hughes.

Golf's top player Johnson is a stroke further back after recording an eagle, two birdies and three bogeys in a mixed bag for the U.S. Open champion, who has won three of eight events this season.

Spieth and Masters winner Sergio Garcia are level at one over following 73s, the latter's display highlighted by his hole-in-one at the iconic 17th hole.

Garcia became the eighth player with a hole-in-one on the flat island green in the PGA Tour tournament's history, while he is the first player to win a Green Jacket and make an ace at a Tour event in the same year since Tiger Woods in 1997.