Former Walker Cup player Cormac Sharvin shot an opening round of 68 to lie joint fourth at the Perth International.
The County Down native, who recently turned professional, shot seven birdies in his round to finish on four under. It could have been better, however, only for a double bogey on the 15th hole.
Paul Dunne, who also featured on the Great Britain and Ireland team that triumphed in the Walker Cup last autumn, carded a 73 and is one over.
Leading the way is American Peter Uihlein on seven under, with Romain Wattel and Shiv Kapur a shot further back.
Uihlein made an encouraging return from a wrist injury at last week's Maybank Championship and made further progress in his rehabilitation by carding 65 at Lake Karrinyup Country Club.
The 26-year-old, whose sole European Tour victory came in 2013 at the Madeira Islands Open, carded bsix birdies and an eagle in his round.
He did start off with a bogey but after swiftly picking up three shots he stunned fans gathered around the four-par ninth hole by sinking his approach for an eagle.
He overtook early starters Wattel and Kapur with three more birdies on the back nine. Strong winds meant he had to make a tough recovery shot on the 15th after hooking his tee shot towards trees.
France's Wattel, who mixed eight birdies with two front-nine bogeys, had already posted his lowest score of the season so far while 34-year-old Kapur of India enjoyed a blemish-free round of 66.
Also shooting four-under 68s were Scott Arnold, Anthony Houston, Todd Sinnott, Nick Cullen, Rhein Gibson, Sweden's Magnus A Carlsson and Brett Rumford, who had abdominal surgery last year.
Defending champion Thorbjorn Olesen signed for 71 while Ryder Cup winner Victor Dubuisson was five over after closing out a disappointing round with a birdie on the last.
John Parry also had a day to forget - the Yorkshireman was eight over at the turn.