David Allen stopped Lucas Browne in three rounds to win their heavyweight showdown at The O2 on Saturday night.
Allen floored Browne with a crunching body shot to claim a stunning victory over the former WBA world champion.
Browne made a busy start and let his hands go early in the first round, while Allen responded by landing a left hook to the body.
The Australian continued fighting on the front foot in the second round and enjoyed success with his jolting uppercut, finding the target through Allen's guard and marking his face.
Allen got caught again in the the third but managed to damage Browne's nose with a heavy uppercut of his own before dropping his man with a superb counter left-hook.
'Big Daddy' was unable to recover and was counted out while on his knees, suffering his second stoppage defeat at the London venue.
"I've proved I can punch at a high level," said Allen. "It's a very good win. The left hook to the body was beautiful.
"I'm the most famous man in Doncaster for a week, it will be great."