Rory McIlroy hit 10 birdies to share the lead with Xander Schauffele and Wyndham Clark at seven under after round one of the Players Championship.
Starting on the 10th, the Northern Irishman had six birdies in his opening eight holes, including on Sawgrass’ iconic par-three ‘island hole’ 17th.
But he dropped shots on the 18th and seventh holes after driving into water.
England’s Matt Fitzpatrick and Canadian Nick Taylor are at six under, while Scottie Scheffler is five under.
World number one Scheffler opened with a bogey on the par-four first but followed that with three birdies and had three more on the back nine as he started his quest to become the first player to defend the title in the 50th playing of the PGA Tour’s $25m flagship event.
Joining the American are Australian Jason Day, winner of this event in 2016, and Swedish sensation Ludwig Aberg who were among six players to shoot 67 on a day of low scoring in Florida.
The tone was set by McIlroy, who was out early at the Florida course. He birdied his opening three holes and rolled in three more in his next five holes.
His first error, a wayward drive into the water down the left of the 18th cost him one shot but he birdied three of his next six holes to reach eight under after 15.
However, another pulled tee shot into water on the seventh cost him two shots.
That followed a 10-minute discussion with playing partners Jordan Spieth and Viktor Hovland about the penalty drop location, and a rules official eventually backed his judgement.
“I think Jordan was just trying to make sure that I was doing the right thing,” said the world number two.
“I was pretty sure that my ball had crossed where I was sort of dropping it. It’s so hard, right, because there was no TV evidence. I was adamant.”
Olympic gold medallist Schauffele did not drop a shot in his 65, while fellow American Clark, who is the reigning US Open champion, had eight birdies, including three on the trot from the 15th as he made it a three-way tie for the lead late on the opening day.
Fitzpatrick, the 2022 US Open champion, is a shot back. He steadied himself after two bogeys in his opening three holes left him one over.
“I thought it was going to be one of those days,” said the Englishman.
Five birdies and an eagle, on the par-five 16th after hitting his second shot to two feet, followed as Fitzpatrick carded his lowest round at Sawgrass.
“I’ve not had the best of form recently but I’ve been working hard and it’s paid off,” he said on Sky Sports. “I need to carry on doing what I’m doing and staying patient.”