On Saturday, March 14th, undefeated Pierce "Big Bang" O'Leary takes on his biggest competition to date when Mark Chamberlain crosses the Irish Sea to fight him for the vacant IBO junior welterweight title in Dublin. (The last holder of this title was Adam Azim in 2025). O'Leary is 18-0 with a career-best win over then-undefeated Hovhannes Martirosyan in 2024. Chamberlain is 17-1-1 and coming off a draw with undefeated Jack Rafferty in August. Joining Chamberlain on the journey will be fellow Brit Colm Murphy (16-0), who takes a massive step up in competition when he fights Irishman Jono Carroll for the vacant IBO junior lightweight title. (The last holder of this title was Anthony Cacace in 2025). At 25-3, Carroll is a certified warrior whose best win saw him retire Scott Quigg in 2020.