Marcus Fraser and New Zealand’s Michael Hendry are the pick of the Australasian players at even par and T28 while defending champion Adam Scott posted a disappointing 2-over 73.
Veterans Phil Mickelson and Lee Westwood are among the group sharing top spot on the leaderboard after both signed for 4-under scores of 67.
England’s Ross Fisher, rising Spanish star Jon Rahm and Americans Jimmy Walker and Ryan Moore are also part of the logjam at the top while World Number Three Rory McIlroy is one shot back sharing seventh.
The elite field, which includes 49 of the world’s top 50 ranked players, found scoring tricky on the Club de Golf Chapultepec layout in Mexico City.
Among those were the Australians, with Scott, in particular, disappointing on day one in what was a roller coaster round.
A birdie at the first looked to set the tone for a good day but he gave the shot straight back at the next then birdied the thirds to get back into red figures.
Six straight pars followed before an inward half that included only one more par among a mish mash of birdies and dropped shots.
A double bogey at 10 was followed by birdie at 11 then back to back bogeys at 12 and 13. A par at 14 the seemed to spark Scott into life and he picked up successive shots at 15 and 16 but undid all the hard work with consecutive bogeys to finish.
But Scott wasn’t the only major winner to find the going tough in Mexico, 2010 Open Champion Louis Oosthuizen also posting a 2-over 73, reigning Masters champion Danny Willett a 76 and 2003 US Open winner Jim Furyk an uncharacteristic 77
Even those at the top of the leaderboard had their fair share of difficulties, Lee Westwood mixing four bogeys with eight birdies while Jon Rahm and Ross Fisher were the only two co-leaders not to post more than one dropped shot.
Newly crowned World Number One Dustin Johnson birdied his very first hole as the top ranked player, one of six gains on the day.
But he also gave back five shots including an ugly double bogey at the drive-able par-4 first, his 10th of the day, where he had to play three off the tee after hitting his first shot through the green into a bush.
While Johnson is still well within reach of the leaders, World Number Three, Rory McIlroy, will be pleased with his first competitive round since fracturing a rib in January.
The four time major winner dropped just one shot on the day to go alongside two birdies and an eagle and at just one back seems likely to be a threat come Sunday.
For the remaining Australians there is plenty of work to do with Sam Brazel posting a 4-over 75, Scott Hend a 5-over 76 and Matt Griffin a 7-over 78.
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