Paul Gallen needed less than two minutes to knock out Lucas Browne in the first round of their fight on Wednesday night in Wollongong.
It was the most impressive knockout yet from the former National Rugby League star who had little trouble dealing with "Big Daddy" who will be paid at least $100,000 in compensation.
The rugby legend landed a big left hand which sent Browne crashing to the canvas as Gallen gave the former WBA heavyweight champion a hiding.
Browne got back to his feet but eventually went down for the second time under a barrage of punches.
Most bookmakers had Browne as the favourite to win, but Gallen upset the apple cart in spectacular fashion, pulling off arguably one of boxing's greatest upsets.
"I knew it was gonna go like that," Gallen said to Fox Sports.
"I said to myself all day and to my team that I'd knock him out in the first round. I've been training to be a boxer for the last 10 months.
"It's amazing what you can do when you set your mind to it. I tore my bicep ten weeks out from the fight so it's amazing what you can do when you put your mind to it."
This was Gallen's 11th win, six via stoppage, of a pro boxing career that started on the undercard of Daniel Geale vs Garth Wood following a short stint as an amateur.
He has now beaten fellow rugby league player John Hopoate, former UFC fighter Mark Hunt and now veteran heavyweight contender Browne.
"I'm a prize fighter, I'm not here for titles. I'm about taking fights that people want to see," he added. "I'll be having as many fights as I can so I can cash in."
And one man who is certainly on his radar is former cross-code star Sonny Bill Williams.
Williams hasn't fought since 2015, but six years after his last fight the 69-test All Blacks centre is planning on making a comeback, and is eyeing a fight with Gallen next.News Now - Sport News