British boxer Mark Chamberlain defeats Pierce O’Leary of the Republic of Ireland in Dublin to win the IBO light-welterweight belt. The fight ends in the 10th round with Chamberlain securing a knockout. Both reports describe how Chamberlain knocks O’Leary down twice during the bout, with the knockdowns setting up the eventual stoppage. O’Leary is unable to continue after the conclusion of the 10th-round action, and Chamberlain is credited with the knockout victory and the championship belt. The accounts focus on Chamberlain’s impact and ability to finish late, highlighting that the decisive outcome comes after a sequence of knockdowns. There are no additional competing claims or differing details between the sources provided beyond the shared description of the result, the venue, the weight class, and the round in which the fight is stopped.