The 36-year-old tapped in for birdie at the par-four 18th to edge out Scotland's Russell Knox and American Jason Bohn, the trio having finished the regulation 72 holes at 18-under-par 266.
McDowell, who had not won on the PGA Tour since the RBC Heritage in April 2013, closed with a five-under 66, Knox with a matching 66 and Bohn with a 68.
McDowell, who had endured a mediocre year by his own standards with just one top-10 in 15 starts on the 2014-15 PGA Tour, was thrilled to see his hard work on the practice range over the past three months finally pay off with a win.
"I've been dreaming of this day and I said that I was going to appreciate it when it came," the 2010 U.S. Open champion told reporters after clinching the third PGA Tour title of his career.
"I'm going to appreciate this one, because this year has been a grind. You go through a year like this and you think, 'Am I finished? Am I not good enough?' You ask yourself all the questions.
"This is a result of three or four months of grinding. I've been working hard on my swing ... and you've got to take the rough with the smooth and keep trying."
Knox, who had led by one stroke with just one hole to play in regulation, had to settle for a runner-up spot in his bid to clinch consecutive PGA Tour titles on different continents.
"I gave it my best shot and got beat by a great birdie there," the 30-year-old Scot said of McDowell's stunning approach on the first extra hole.
Knox, who eight days ago won the WGC-HSBC Champions in Shanghai, was at 19 under playing the 18th at El Camaleon but hit his tee shot into a fairway bunker en route to a bogey, forcing a three-way playoff for the title.
Twenty-seven players had been unable to complete the 72 holes on Sunday after the final round was interrupted by inclement weather that led to a delay of nearly four hours.
(Reporting by Mark Lamport-Stokes in Los Angeles; Editing by Frank Pingue)
Share
