In what many felt was a shocking outcome, Paul Gallen secured the biggest victory of his boxing career, when he crushed the far more experienced Lucas Browne with a first round knockout.

Very early in the round, Gallen dropped the former WBA heavyweight champion with a hard left hand.

Browne was able to get back to his feet, but it was simply the beginning of the end. 

He was quickly caught against the ropes and dropped for a second time from a series of follow-up punches.

The packed venue of fans went wild at the WIN Entertainment Centre in Wollongong.

Gallen (11-0-1, 6 KOs), who made nearly half a million for the contest, was widely viewed as a big underdog, with many observers tabbing Browne to pull out the knockout victory.

A former professional rugby league player who captained the Cronulla-Sutherland Sharks in the NRL to their maiden NRL Premiership in 2016, Gallen was given a tremendous amount of motivation from past and current players of the Cronulla Sharks.

"I had confidence in my chin against a guy like this," Gallen said.

"The more I train and the more I spar in the sport of boxing the better I get."

There now talk of Gallen facing rising Olympian Justin Huni, who Browne himself was scheduled to face.

Gallen is very pumped to continue his boxing career. He has no interest in world title fights. The unbeaten fighter wants the biggest and most lucrative opportunities possible.

"I'm a prize fighter, I'm not here for titles. I'm about taking fights that people want to see. I'll be having as many fights as I can so I can cash in," Gallen said.