Gary "Spike" O'Sullivan charged out of his corner at the sound of the opening bell and tore into Nick "The Machine" Quigley with a sustained, two-handed assault that didn't subside until referee Arthur Mercante stopped the fight at the 1:23 mark of the fourth round.
The scheduled 10-round middleweight bout, emanating from the House of Blues, was a rout. The courageous Quigley (15-3, 3 KOs) did his best to fight back but didn't have the punching power to keep up with the rampaging O'Sullivan.
The Irishman unloaded with wicked hooks to the body and solid rights to the head as they stood toe-to-toe throughout most of the fight.
The ringside doctor examined Quigley after the third round but let the fight continue.
The 29-year-old Quigley, from Liverpool, was having his first fight in 19 months, which seemed to affect his timing. He was cut on the left eyebrow and bleeding from the nose when the fight was stopped. There were no knockdowns.
The colorful O'Sullivan (26-2, 18 KOs) also suffered a cut over his left eye. He sports a handlebar mustache and claims to be a distant relative of John L. Sullivan, the last bareknuckle heavyweight champion.
The 33-year-old winner is campaigning for a shot at middleweight champion Gennady Golovkin but will need wins over more accomplished boxers than Quigley to earn the opportunity.
In the junior lightweight co-feature, Dardan Zenunaj scored three knockdowns en route to a third-round technical knockout of Filipino Reckay Dulay. Zenunaj (14-3, 11 KOs) is an Armenian living in Belgium but currently fighting out of Oxnard, California. Dulay's record fell to 10-3, with seven KOs.