"I've been disappointed that I haven't kicked on better this year, to be honest," McDowell, 37, told reporters while preparing for Thursday's opening round at El Camaleon Golf Club.
"Finishing with the type of momentum I did last year, I really felt like I was going to kick on a little bit more.
"But taking the positives out of this year, when I have played well, I've maintained my weekends and continued to play well and posted several good rounds. The inconsistencies have been those missed cuts."
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The straight-hitting McDowell, whose only major victory came at the 2010 U.S. Open, missed the cut last week at the Shriners Hospitals for Children Open in Las Vegas on his first start on the 2016-17 PGA Tour.
Overall, though, the globe-trotting Northern Irishman is in upbeat mood for his title defence at Playa del Carmen where he triumphed last year in a three-way playoff.
"It is a challenge that we face year on year, trying to work out how to schedule ourselves as well as we possibly can, stay as fresh as we possibly can, especially for a guy like myself playing both the PGA Tour and the European Tour," said McDowell.
"It's a balancing act, but I feel like I've learnt something new about my schedule every year ... I'm feeling very fresh and very much looking forward to defending my title this week at the OHL.
"I'm as motivated and as healthy and as mentally fresh as I have been in a long time, and it's just a case of being really patient with it now ... I'm feeling good with where I'm at with my game."
Among those also competing this week at El Camaleon are former world number ones Ernie Els and Luke Donald, PGA Tour veteran Jim Furyk, Argentina's Emiliano Grillo and Japanese Ryo Ishikawa and Anirban Lahiri of India.
(Reporting by Mark Lamport-Stokes in Los Angeles; Editing by Frank Pingue)
