Rafa Cabrera Bello opened with a 65 at Bay Hill, and leads the Arnold Palmer Invitational by two strokes after day one.
The 34-year old Spaniard mixed a field-best eight birdies with one bogey en route to a low-round 7-under par.
“I really didn’t know what to expect. I know how nice and tough the course is and I think it’s a course with many, many daunting shots, so I feel the more you play it, probably the better,” said Cabrera Bello, who hit 8 of 14 fairways and 13 of 18 greens.
“So I wasn’t really having much high expectations as opposed to just getting out there and playing my golf.
“Don’t get me wrong, I do think the course suits me and I’m going to try my best and I’m happy the way I’m playing, the way I’ve been playing this year, so I’m just really pleased with the round and happy to be here at Bay Hill.”
Alone in second-place, and two off the pace, was Keegan Bradley, who shot a bogey-free 5-under 67.
A group of five players were one further back on 4 under, headlined by a pair of two-time Masters champions in Bubba Watson and Phil Mickelson, who finished with three bogeys against seven birdies.
“It’s just not as easy as it looks. So I was pleased that I hit a lot of overall good shots, made a lot of birdies,” said Mickelson, who won at Bay Hill in 1997.
“That’s a lot of birdies out there, seven of them, I didn’t expect that.”
Billy Horschel, Graeme McDowell, and Patrick Rodgers were the others in the T3 group, alongside Watson and Mickelson.
Defending champion Rory McIlroy struggled to an even-par 72, which included four bogeys and four birdies, to sit T49.
“It’s tricky out there, the conditions are pretty tough, the course is drying out already. With the way the forecast is, it’s only going to get even trickier as the week goes on,” said McIlroy.
“So I’m three shots off the top-10, if I go out tomorrow and shoot something in the 60s, I’ll be right there for the weekend.”
Jason Day, the 2016 champion, withdrew after six holes, citing back pain.
First-Round Leaders
1. Rafa Cabrera Bello 65 (-7)
2. Keegan Bradley 67 (-5)
3. Graeme McDowell 68 (-4)
3. Patrick Rodgers 68 (-4)
3. Bubba Watson 68 (-4)
3. Phil Mickelson 68 (-4)
3. Billy Horschel 68 (-4)