The Australian contingent will rue late stumbles after Englishman Paul Waring claimed the surprise first-round lead at the PGA Tour's all-important Houston Open.
Waring fired a seven-under-par 63 without a bogey to earn a one-stroke advantage over former US Open champion and 2025 runner-up Gary Woodland.
Woodland's fellow Americans Sam Burns, Michael Brennan and Tom Hoge all shot 65s at Memorial Park Golf Course to land in a tie for third.
Australian Karl Vilips was making a push for the lead after surging to five under through 12 holes before faltering down the stretch.
Three bogeys in his last five holes left Vilips lamenting a two-under round of 68 that left him in a tie for 31st and playing catch-up in pursuit of the second-last Masters spot up for grabs ahead of the year's first major championship starting in two weeks.
Former Masters champ Adam Scott is the leading Australian at three under and tied for 11th but he too was left frustrated by a sloppy bogey at the par-4 17th, where he inexplicably drove into the water.
Aided by an ace at the par-3 15th, American Cole Hammer is also three under after his rare scorecard featured a 1, 2, 3, 4, 5.
Fellow former world No.1 Jason Day and defending champion Min Woo Lee posted 68s like Vilips.
Playing with Scott, Lee also bogeyed the 17th after missing a short par putt, while Day, in contrast, rallied with five birdies after his troubles started early on Thursday with a double bogey on his third hole.
At least Scott, Day and Lee are exempt for Augusta National, unlike Vilips and leader Waring, who rammed in seven birdies in a bogey-free start.
Waring is playing on a medical exemption after making just two cuts as a PGA Tour rookie in 2025 and battling a shoulder injury.
Woodland, who tied for second last year with world No.1 Scottie Scheffler, played without a bogey until the seventh hole - his 16th of the day - and bounced back with birdies on the next two holes.
England's Marco Penge (66) had a bogey-free round and is tied for sixth place with Kurt Kitayama, Germany's Stephan Jaeger and England's Mike Wallace at four under.
Rickie Fowler, who needs a strong result or a win at next week's Texas Open in order to qualify for next month's Masters, posted 67.
Five-times major winner Brooks Koepka, who helped redesign the course, finished with 75.
With Reuters
