Russell Henley finally made a bogey, and that's about all that went wrong for him as he closed with a one-under 70 for a four-shot victory at the PGA Tour event in Mexico.
Henley enjoyed a six-shot lead going into the final round at El Camaleon on Sunday but had the lead reduced to three when he missed a five-foot par putt on the par-5 fifth hole.
He responded with three straight birdies, and no one got closer than four shots the rest of the way.
Henley won for the fourth time on the PGA Tour, and the first time since the Houston Open five years ago, moving to No.33 in the world and assured of returning to the Masters.
The previous five times Henley had at least a share of the 54-hole lead, he failed to convert the victory. The most recent was the Sony Open in January, when Hideki Matsuyama made up a two-shot deficit and beat him in a playoff.
"I just tried to learn from my past and my screw-ups," Henley said with a smile.
"All those events I didn't close out, they hurt. You never know if you'll win another. To come down 18 with a four-shot lead was really cool."
Henley finished at 23 under to tie the tournament record. He came into the final round as the only player who had not made a bogey all week.
"It's tough. I don't sleep well on a lead. I need a lot more practice," Henley said.
"I have no idea how Tiger did this 80-some times. It's tough for me just to kind of calm down. You definitely don't feel the same as when you're practising at home, but that's the fun of it. That's why we play.
The victory also sends Henley to Kapalua in January for the Sentry Tournament of Champions, the first elevated event in a new year of big purses.
Fellow American Brian Harman (66) finished alone in second, while the group five shots behind included Masters champion Scottie Scheffler and Seamus Power of Ireland, who was coming off a victory last week in Bermuda.
Scheffler lost the No.1 ranking he had held since March when Rory McIlroy won the CJ Cup two weeks ago. Scheffler closed with a 62 at Mayakoba, leaving him a good chance to reclaim the top ranking next week at the Houston Open.
Power (68) tied for third with Scheffler, Joel Dahmen, Troy Merritt and Will Gordon to put the Irishman atop the FedEx Cup standings and move him to No.29 in the world, his highest ranking ever.
Australia's Jason Day shot a final-round five-under-par 66 to finish joint-21st at 14 under.