Min Woo Lee increased his advantage with a second consecutive five-under-par round off 66 and will take a three-shot lead over Japan's Rikuya Hoshino into the final round of the Australian PGA.
Lee opened his day at Royal Queensland with two birdies in the first three holes to increase his advantage over the former Masters champion, Adam Scott.
However, his lead was reduced back to a single stroke after bogeys at both of the front nine's par-threes when he stepped off the 10th green.
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"It's a course you can shoot low, so you'll be aggressive no matter what," Lee said, who finished tied fourth at last year's event.
"I'm here because I played aggressively I can just control what I can do and if someone goes out and shoots low, hopefully I finish the day happy with how I've played.
Scott's inconsistency allowed Lee to restore his advantage as a birdie at the 12th was followed by another at the par-five 14th.
This allowed the emerging Australian player to open up the gap on the chasing pack as he looks towards securing a third win on the DP World Tour.
Reigning champion Cameron Smith made an emotional exit at the Australian PGA Championship on Friday after he missed the cut by nine shots.
Hoshino (64) hit six birdies on the back nine to claim outright second at 14 under, while Curtis Luck hit a five-under-par round of 66 to move into third place with Connor Syme and Lucas Herbert a further shot adrift in a share for fifth. Scott signed for a level-par 71 and is six shots off the lead.