New Zealander Danny Lee leads the Mayakoba Classic by one stroke after firing a nine-under par 62 in the opening round.
South Korea-born Lee was out in 29 at the El Camaleon course in Mexico's Playa del Carmen, helped by an eagle on the fifth, and was 10-under after 13.
At that stage Lee had thoughts of shooting a sub-60 round, only to three-putt from 15 feet on the 14th for his only bogey, before finishing with four pars.
"Definitely, it was in my head, 59 or 58," said Lee on pgatour.com.
"I have never shot that score out on the PGA Tour before, so I really wanted to make that happen.
"On 14, I had a less than a 15-footer for birdie. Just one of those days I felt like I can make anything. I just gave it a little too much extra and hit it through the break and missed the next one coming back.
"I was a little bit bummed out on that one. But still, nine under is a great start."
Lee said he'd made changes to his swing and was finally starting to feel comfortable with the adjustment.
"I changed my swing a little bit to gain distance off the tee, and I really feel like the new swing is grooving into my body now," he said.
"I feel very comfortable with all my clubs, and with my wedges. It's been showing me a lot of good results."
American duo Adam Long and Brendon Todd are tied for second on eight under.
Jason Day and Aaron Baddeley are the best-placed Australians, sitting eight shots off the lead at one-under 70. Compatriots Matt Jones and Rhein Gibson are a further shot behind.