Chamberlain stops O'Leary in tenth to win IBO title in Dublin

Mark Chamberlain knocked out defending IBO light-welterweight champion Pierce O'Leary in the tenth round at the 3Arena in Dublin on 1 August 2026, silencing a capacity crowd of around 7,000. Chamberlain, now 18-1, survived a seventh-round knockdown from a body shot to hand O'Leary his first professional defeat. The win came in Chamberlain's first fight since drawing with Jack Rafferty the previous summer.