Argentinean Emiliano Grillo showed his first real signs of nerves as powerhouse American duo Jason Dufner and Bo van Pelt made their charge at the $2 million Perth International.
Grillo started the day with a four-stroke lead over West Australian Jason Scrivener and world No.24 van Pelt, and at one point increased his buffer to five shots before four bogeys on the back nine saw him surrender the lead.
Van Pelt ended the day on top of the pack at 12-under after a five-under 67, while world No.10 Dufner carded the same score to be just one shot adrift of his countryman.
Grillo, at just 20 years of age and ranked a lowly 516th in the world, is third at 10-under and will need to regain his magic touch on Sunday if he is to snare his first professional win.
England's David Howell and Spain's Alejandro Canizares sit in equal fourth at seven under, while defending Australian Open winner Greg Chalmers, Kiwi Michael Hendry and big-hitting Aussie Steve Jones are one stroke further back.
Chalmers, who shot a three-under 69 to move within striking distance of the leaders, hoped for windy conditions on Sunday to boost his chances of snaring an unlikely victory.
"I think it's doable," Chalmers said of chasing down the leading pack.
"No one's torn up this golf course yet, and I think there's a seven-under out there or an eight-under if you drive the ball in play and things go your way.
"You have to tear the par fives up and most of them are reachable at the moment.
"If you can do that and pick up two or three more somewhere else, you're going to have a big day."
Van Pelt holed a monster 55-yard putt on the 18th to finish the day on the perfect note.
"Once in a while the hole just gets in the way," van Pelt said with a smile.
"I was just trying to get the ball down there and two-putt. Lo and behold, the thing goes in the hole.
"It's just nice to finish with a birdie like that and hopefully I'll take that momentum in tomorrow."
Van Pelt said Grillo remained a big threat heading into the final round despite his slip-ups on the back nine.
"He played a lot better than his score today," van Pelt said.
"For such a young player, his upside is tremendous. He's going to have a great career and win a lot of tournaments.
"He probably had five or six putts that looked like they were going to go in, but hit the edge.
"That's just golf. Some days they go in, other days they hit the edge."