The 40-year-old American was playing just his third tournament since returning from an eight-month absence.
The 40-year-old American was playing just his third tournament since returning from an eight-month absence recovering from shoulder surgery.
"I was really calm," said Perez, adding that a more aggressive mindset had him feeling confident his comeback could produce his first victory since the 2009 Bob Hope Classic.
"I just had a lot of confidence when I came back," he said. "I started about 2 1/2 months ago and I didn't think it was going to happen this fast, but I thought it was going to be pretty successful, my comeback."
His five birdies came in his first eight holes on the Greg Norman-designed El Camaleon course in Playa del Carmen, and after one blip, a bogey at the 12th, he parred his way home to triumph with a 21-under par total of 263.
He was two shots in front of overnight leader Gary Woodland, who closed with a 70 for 265.
Scotland's Russell Knox was alone in third after a 66 for 266.
Kevin Streelman (65), Chez Reavie (67) and Scott Piercy (70) tied for fourth on 267.
Woodland got off to a slow start with bogeys at the first and third, but he claimed the last of his four birdies at 17 and 18 to secure second place.