American Patrick Reed aced the Watering Hole but has one regret, while England's Sam Horsfield has none after setting the first-round pace at LIV Golf's Adelaide tournament.
Horsfield carded a blemish-free six-under 66 at The Grange on Friday to hold a one-stroke lead from Chile's Joaquin Niemann and Mexico's Carlos Ortiz.
Major winners Dustin Johnson and Bryson DeChambeau lurk a further shot behind, but Australia's Ripper GC made a sluggish start to their team title defence in Adelaide.
Lucas Herbert (one under) was the best of the locals with Cam Smith at even par, Marc Leishman one over and Matt Jones finishing three over.
Reed's hole-in-one at the party hole, the par-3 12th, came just 15 minutes into Friday's opening round.
His sweetest of shots is the second ace at the hole in LIV Golf's three events in Adelaide, after Chase Koepka's hole-in-one in 2023.
Reed was immediately showered with drinks thrown by crowds lining the rowdy hole.
But the 34-year-old lamented being unable to harness the momentum - he carded a three-over 75.
"Besides that one hole, it was ugly," Reed said.
"The crazy thing was the adrenalin afterwards.
"I was shaking going back to the tee and just couldn't kind of calm down and settle into the round after that point."
Australia's quartet failed to fire despite raucous support from a 35,000-strong crowd.
Herbert shot five birdies but was stymied by a double-bogey and two bogeys, including at the Watering Hole.
Leishman birdied the party hole for the fourth consecutive time at the tournament, while fan favourite Smith endured a roller-coaster round with four birdies mixed with four bogeys.
Leader Horsfield got hot with three birdies in a four-hole stretch midway through a round he rated as "nice" in front of the massive crowds.
"One thing about the Aussie fans is they really understand the game of golf," the 28-year-old said.
"It's a once-a-year event. You have got to embrace it, you've got to have fun with it and ... let them get behind you and try to put on a show for them."
DeChambeau and Johnson are within striking distance, as are fellow major winners Brooks Koepka (three under), Jon Rahm (two under) and Bubba Watson (two under).
"It was a battle out there, this golf course had a lot of bite to it," said DeChambeau, who was four under through nine holes.
Spaniard Sergio Garcia is one under and another popular veteran, American great Phil Mickelson, is even par.
Another Australian in the field, Wade Ormsby - who is a member at The Grange and competed as an injury replacement for Iron Heads GC - had a torrid time, shooting seven over.
Torque GC, which features Ortiz and Niemann, top the team standings with a combined eight under, some 11 strokes clear of Smith's Ripper GC.
