Marcus Fraser capitalised on a late stumble from Lee Soo-min to claim his third European Tour title at the inaugural Maybank Championship Malaysia in Kuala Lumpur.
Fraser carded his second-straight bogey-free round, a 68, to finish on 15 under - a total that secured a two-shot victory thanks to Lee running up double bogeys at two of the last three holes.
In only his second European Tour start, Lee had led by three strokes heading into the final day and was still two clear of Fraser on the 16th tee.
However, the South Korean then faltered badly and Fraser took full advantage - holing clutch par putts from 10 and 15 feet respectively on the 17th and 18th.
"The last two outs were unbelievable," said Fraser, whose last European Tour victory came at the Ballantine's Championship in 2010.
"I was pretty nervous on 17, and then I don't know how I held onto the putter just trying to stand over that one on the last, I was pretty nervous.
"Luckily I made contact and it started somewhere where it was supposed to and went in the hole. I'm just gobsmacked at the moment."
The Australian said he felt there was always a chance his 22-year-old opponent would drop shots.
"In the back of my head I felt I had a chance," Fraser added.
"He's quite young and it's a big thing to be leading a European Tour event with a few holes to go, so I just kept reminding myself to breath and just play my own game and see what I could do.
"Somehow a lot of putts found their way into the hole over the week."
Lee, who ultimately signed for a 73, shared second place on 13 under with Miguel Tabuena (68).
France's Julien Quesne and Spaniard Jorge Campillo were a shot further back following respective rounds of 68 and 69.