Victorian Blake Collyer further enhanced his reputation for cutting down higher-ranked opponents to advance to the Australian amateur championships second round.
Collyer utilised local knowledge to beat second seed Anthony Quayle two-up in a high-class first round duel that continued right to Metropolitan's 18th green.
"It was a really good match, we both played really well. I guess, I sank some putts when I needed to,'' the victor said.
It's a repeat scenario for Collyer after he saved par from a greenside bunker at the 10th hole in the morning to survive a play-off just to make the 64-man matchplay field.
A member of Metropolitan's pennant team, he cut it fine in a similar qualifying rounds play-off in last year's national championships at The Australian before knocking out a high seed in the first round on his way to the last 16.
"I guess knowing the course really helped me. It gave me some confidence and I felt good out there,'' he said.
On his chances of advancing further this time, Collyer said: "That's the plan. I feel I've got the game to."
Collyer's sub-par upset performance was the local standout on a fine day for the NSW men with Dylan Perry ousting recently crowned Victorian amateur champ Cameron John one-up.
Harrison Endycott won 1-up against Japan's Takumi Kanaya, Corey Jones beat England's Bradley Moore 2 & 1 and Austin Bautista thrashed Welshman Jack Davidson 5 & 4.
Medallist and top seed Charles Pilon continued his good form with a 3 & 2 victory over fellow Australian Haydn Barron.
Golf Australian national squad member Brett Coletta had to work hard to shake off gallant 14-year-old fellow Victorian Karl Vilips 2 & 1.
Curtis Luck, Australia's highest ranked amateur, is out, beaten 2-up by South Korea's Je-chang Ryu.
Scot Grant Forrest, runner-up in the 2015 British amateur, led the overseas challenge with a 3 &2 win against Australian Kevin Yuan.
William Heffernan is through the next round after a 3 &2 win agains Fred Lee, while fellow Victorian DJ Loypur was even more impressive with his 6 & 5 triumph against Anthony Marchesani.