Patton Kizzire held off a back-nine charge from Rickie Fowler to claim a maiden PGA Tour victory at the OHL Classic at Mayakoba.
The world No 236 carded a bogey-free 67 in breezy conditions at Playa del Carmen, where 13 players were forced to complete 36 holes on Sunday due to weather delays earlier in the week.
Kizzire posted four birdies in a flawless display to set the clubhouse target at 19 under, with Fowler one back in second despite finishing his third consecutive 67 with three birdies in his final six holes.
"It was nerve-racking but I felt good," Kizzire said. "I've been in tough experiences before and I drew from that. I'm pretty excited and was glad to get it done."
Fowler bogeyed the first and slipped three behind when Kizzire rolled in from five feet at the second, only to respond with back-to-back gains over his next two holes.
Kizzire also picked up a shot at the fourth and added another at the par-five fifth, where Fowler found the water twice on his way to bogey, to extend his advantage to four strokes.
A long-range birdie at the sixth kept Fowler within three of the lead at the turn, as Kizzire almost holed out from the fairway on leave a kick-in at the 11th.
Fowler nudged in from four feet to birdie the 13th and holed a 15-footer at the 16th to close the gap to two, before converting from a similar distance at the 17th to halve Kizzire's cushion.
As Fowler left his birdie attempt at the last short in his attempt to force a play-off, Kizzire found the green in two and two-putted for par to complete his one-shot victory.
Si Woo Kim grabbed third spot after posting five straight birdies from the fifth and bouncing back from a double-bogey on his back nine to close out a six-under 65.
Charles Howell III carded back-to-back 66s to join Martin Piller in fourth spot on 14 under, with Russell Knox a further two strokes back in tied-ninth after a three-under 68.