Rory McIlroy claimed the first-round lead at the Honda Classic with a seven-under 63.
The Northern Irishman came home in 30 shots and signed off with back-to-back birdies to finish the opening day one clear of American Russell Henley.
McIlroy rolled in a 27-foot birdie putt at the second and tapped in at the par-five third to pick up another shot.
He birdied three in a row from the 10th and added another with a 12-foot putt at the par-three 17th.
At the 18th, McIlroy found a bunker with his approach but blasted out inside five feet and sank the putt.
McIlroy's victory at this event two years ago earned him the world No 1 ranking for the first time in his career but he made a humbling withdrawal in 2013 during the second round, complaining of mental fatigue and toothache.
Henley took advantage of the same stretch of holes at PGA National as McIlroy, in his case birdieing four in row from the 10th in a bogey-free 64.
Welshman Jamie Donaldson is part of the group sharing third place, a stroke further back. South Africa's Rory Sabbatini and American William McGirt matched Donaldson's 65.
World No 1 Tiger Woods blamed his inconsistency with the putter after an opening 71 left him eight adrift.
"I hit it probably good enough to shoot at least three or four lower than I did," said Woods.
"First four holes, I had good looks (at birdie putts) and didn't make any of them. I hit it good starting out, scrappy in the middle and good at the end."