American Matthew Wolff fired a 10-under-par 61 on Thursday, setting a course record and seizing a two-stroke lead after the first round of the US PGA Mayakoba Championship.
The bogey-free effort matched the lowest round of Wolff's PGA career and left him two strokes ahead of compatriot Aaron Wise, who made seven birdies and an eagle against a lone bogey.
"It was very steady, birdies kind of came evenly throughout the round, didn't really make any mistakes," Wolff said. "Every single shot I was comfortable over, I was committed to.
"I didn't know it was a course record. That's really cool to hear."
Chris Kirk, in the first group off the back nine, began his round with a hole-in-one at the 204-yard par-3 10th. He was the first player to start a US PGA round with an ace since US countryman Keith Mitchell on the same hole in the opening round in 2017.
"Made me feel a little better about my 4:30 wake-up call this morning," Kirk said. "Got to land it short so perfect 6-iron for me. I hit a really good shot.
"It was still kind of overcast and dark, and walking up, as we got close to the green, it was like there's not a ball there. My caddie, was like, 'I swear I saw it rolling on the green,' so I was like, 'It's either in or just over in the rough,' and sure enough."
Kirk fired a 64 to share third with Spain's Sergio Garcia and Americans Talor Gooch and Billy Horschel.
American John Huh, whose only PGA victory came nine years at Mayakoba, made the second ace of the day and 16th in tournament history at the par-3 eighth from 139 yards.
Wolff, who took a couple of months off in the spring to handle mental issues then contended in June's US Open at Torrey Pines, began his round with a birdie at the 10th then birdied four of the last six holes on the back nine.
After a birdie at 18, he opened the front side with back-to-back birdies, added two more at the par-5 fifth and seventh holes and closed his round with his 10th birdie.
"The putts definitely dropped," said Wolff. "I had a lot of short makeable putts. When you shoot 10 under, you kind of have to make all them and those are the ones I did make. I was hitting the ball really good all day."