Mark Chamberlain Knocks Out Pierce O’Leary to Win IBO Title

Chamberlain’s Early Knockdowns and the Battle in Dublin

The high-stakes 12-round main event delivered intense momentum shifts in front of a capacity crowd of around 7,000 spectators in Dublin. Fighting out of a southpaw stance, Portsmouth’s Mark Chamberlain caused immediate tactical problems for the home favorite, controlling the distance and neutralizing O’Leary’s early advances according to sports reporting.

The challenger made his first major breakthrough late in the second round. A flush left hand caught Pierce O’Leary and sent him flying back onto the canvas, leaving the defending champion bleeding heavily from the nose. O’Leary’s struggles continued into the third round when Chamberlain landed another short left hook at close range, sending the Dubliner down for a second time and establishing a commanding lead in the 140lb division bout.

O’Leary’s Seventh-Round Resurgence and the 3Arena Crowd

Buoyed by the raucous home support, O’Leary refused to fold under the early pressure. He gradually worked his way back into the contest by pressing forward from the fourth round onward and targeting Chamberlain’s body. The momentum shifted dramatically at the end of the seventh round when O’Leary trapped his opponent near the corner and floored him with a punishing body shot.

Chamberlain was slow to get to his feet but survived the count as the bell sounded immediately afterward. Energized by the knockdown, O’Leary continued to press the action through the eighth and ninth rounds, forcing the tiring challenger onto the defensive and bringing the Dublin crowd to its feet.

The 10th-Round Stoppage and Post-Fight Reactions

The fight ended abruptly in the 10th and final round.

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The victory advanced Chamberlain’s professional record to 18 wins, one defeat, and one draw, while O’Leary dropped to 19-1 following his first professional loss. Speaking after the bout, Chamberlain paid tribute to his opponent and addressed his willingness to fight away from home on enemy territory.

“First and foremost, respect to Pierce, massive thank you to Queensbury, Frank, and Piece for giving me this opportunity… I’m not a stranger to an away day, and anyone that knows me deep down knows I will fight anyone, anywhere. If means I’ve got to go in the champions back garden, I’ll do that. But I take my hat off to Pierce because he’s a true champion and he’ll come again.”

Mark Chamberlain, via RTE

Promoter Frank Warren stated immediately after the fight that a rematch could take place between the pair, with Chamberlain expressing interest in hosting a subsequent bout in his hometown of Portsmouth.

Undercard Highlights at the 3Arena

The supporting card featured several notable domestic matchups and title fights promoted by Queensberry Promotions. In the chief support bout, British and Commonwealth super-featherweight champion Royston Barney-Smith outclassed Reece Bellotti across 10 rounds to capture the vacant IBO intercontinental belt, moving his undefeated record to 17-0 since turning professional in 2022.

Steven Cairns advanced to 14-0 with a fifth-round technical knockout over Senan Kelly, and heavyweight Adam Olaniyan maintained his 100% stoppage record by defeating Deepak Pathak in the second round ahead of his scheduled September appearance.