Emiliano Grillo extended his lead by moving to 12 under par when the third round of the ISPS HANDA Perth International began at Lake Karrinyup.
The 20 year old Argentine, on course to secure his European Tour card after starting the week 112th on The Race to Dubai, opened with five straight pars after beginning the day four shots clear.
The Qualifying School graduate then rolled in a 12 foot birdie putt at the sixth, the hardest hole on the course, to stretch his advantage to five.
America’s World Number 24 Bo Van Pelt had narrowed the deficit to three with a birdie at the first, but bogeyed the sixth to drop back to level par for the day and seven under for the week.
That was one ahead of Australian Steven Jones, New Zealander Mark Brown, Spanish first round leader Alejandro Cañizares and World Number Ten Jason Dufner – the highest-ranked player in the field.
The US Ryder Cup star had an eagle at the third, but bogeys at the first and fifth prevented him closing in on Grillo.
Dufner chipped in for birdie at the seventh to join Van Pelt on seven under, and although he was five clear Grillo's nearest challengers were the two highest-ranked players in the field.
On Friday Grillo had holed his approach to the ninth for eagle, and while he could not repeat the trick form a fairway bunker, he did get up and down for birdie.
He bogeyed the next, however, and was suddenly only two ahead as Dufner recorded a hattrick of birdies from the ninth.