Pierce O’Leary defends his IBO super-lightweight title against Mark Chamberlain at Dublin’s 3Arena on Saturday 1 August 2026. DAZN’s UK coverage starts at 7pm BST, with the main-event ring walks expected at roughly 10pm.
They were meant to settle this in March. Chamberlain fell ill, Maxi Hughes stepped in and O’Leary turned a stressful homecoming into the finest night of his career. Five rounds later, the Dublin crowd had a new champion.
Now the original opponent is back. Chamberlain is taller, a southpaw and the heavier puncher on paper. He has also gone 12 hard rounds in hostile territory before. O’Leary has home advantage and an unbeaten record, but this is no ceremonial first defence.
O’Leary vs Chamberlain Date, Venue and Key Details
Fight: Pierce O’Leary vs Mark Chamberlain
Date: Saturday 1 August 2026
Venue: 3Arena, Dublin, Ireland
Title: O’Leary’s IBO super-lightweight championship
Distance: 12 rounds
UK card start: 7pm BST
Expected ring walks: Around 10pm BST
UK broadcaster: DAZN
O’Leary record: 19-0, including 11 stoppage wins
Chamberlain record: 17-1-1, including 12 stoppage wins
The show is promoted by Queensberry and has been billed as “No Turning Back”. It is a fitting name. O’Leary is trying to turn one famous Dublin night into a genuine run at the top of the division. Chamberlain may not get a better chance to shake up the 140lb picture.
What Time Is O’Leary vs Chamberlain in the UK?
The main card is due to begin at 7pm BST on Saturday. O’Leary and Chamberlain should make their ring walks at around 10pm.
That second time is an estimate rather than a promise. There are several scheduled 10-round contests beneath the headliner, and an early stoppage or a string of decisions can shift the running order. Anybody tuning in only for the title fight should be ready before 10pm.
Dublin and the UK use the same local time in August, so British viewers do not need to make a conversion. The doors at the 3Arena are listed for 4pm, several hours before the main broadcast begins.
How to Watch O’Leary vs Chamberlain in the UK
Pierce O’Leary vs Mark Chamberlain will be shown live on DAZN in the UK. The card can be watched through the DAZN app or website on a compatible device.
Coverage is listed from 7pm BST. DAZN’s live schedule should still be checked on fight day in case the running order changes.
The event is not currently presented as a separate UK pay-per-view. Access will depend on the viewer’s DAZN subscription, so it is worth checking the account and current plan before the first bell rather than at 9.55pm.
Why Are O’Leary and Chamberlain Fighting Now?
This matchup has already survived one cancellation. O’Leary and Chamberlain were originally booked to fight for the vacant IBO belt in Dublin on 14 March. A serious chest infection forced Chamberlain out around two weeks beforehand.
Hughes accepted the replacement fight and gave O’Leary a respected name for his first professional appearance in Dublin. The size difference soon told. O’Leary pressed with control, worked the body and repeatedly found the target until Hughes retired on his stool after the fifth round.
The victory made O’Leary the IBO champion. That organisation sits outside the WBA, WBC, IBF and WBO quartet covered in our guide to boxing’s governing bodies, but the belt and the occasion still give this fight real consequence. Both men have also appeared in the WBC rankings, leaving the winner well placed to chase a route towards one of the four major titles.
There is a personal edge too. O’Leary questioned whether Chamberlain still had the same hunger after his run on major Riyadh Season cards. Chamberlain dismissed the Dublin atmosphere as outside noise. Neither man has spent the build-up pretending this is merely business.
Pierce O’Leary Record and Recent Form
O’Leary enters his first defence with 19 wins from 19 professional fights and 11 victories inside the distance. He is 26 years old, stands 5ft 8in and fights from an orthodox stance.
His rise has not been built on knockouts alone. O’Leary won the WBC International belt over 10 rounds and later outpointed Liam Dillon to add the European super-lightweight title. Against Dillon, he showed the patience to manage a full championship fight rather than chase the finish.
There have been sudden endings as well. Hovhannes Martirosyan lasted into the ninth before O’Leary caught him, while Braian Ronner was stopped in the final round of an eight-round contest. The Hughes victory was different again: less one dramatic punch, more a steady takeover that convinced the corner to call it.
That adaptability is the best argument for the champion. O’Leary can close distance behind a high guard, punch around the elbows and then take a small step out before the reply. He is happier at mid-range than his nickname might suggest.
The March homecoming matters beyond the result. O’Leary grew up close to the 3Arena and carried the expectations of a sold-out crowd into his first professional bout in the city. He now knows what that walk feels like. Chamberlain can still make the evening uncomfortable, but the occasion itself should not overwhelm the champion.
Mark Chamberlain Record and Recent Form
Chamberlain travels to Dublin with 17 wins, one loss and one draw. Twelve of his victories have come by stoppage, a stronger finishing percentage than O’Leary’s. The 27-year-old from Waterlooville stands around an inch taller and fights southpaw.
His reputation changed quickly on the Saudi cards. Chamberlain looked destructive at lightweight, tearing through Gavin Gwynne and Joshua Oluwaseun Wahab before a surprise defeat to Josh Padley at Wembley in September 2024. Padley dropped him and took a clear points decision.
It could have been the start of a slide. Instead, Chamberlain moved into another demanding away fight against unbeaten British and Commonwealth champion Jack Rafferty. Their 12 rounds in Altrincham became a bruising, high-output contest. One judge favoured Rafferty, but the other two scored it level, producing a majority draw.
The record therefore needs a little context. Chamberlain has won only one of his last three, yet the draw with Rafferty proved he could fight hard for 12 rounds at super-lightweight. He took clean shots, kept returning them and finished strongly enough that many viewers felt he had done more than the cards suggested.
Inactivity is the concern. Chamberlain has not boxed since that Rafferty fight in August 2025, and illness then removed him from the original O’Leary date. Eleven months away is not ideal preparation for an opponent who applies educated pressure from the first round.
O’Leary vs Chamberlain Style Breakdown
O’Leary is orthodox and Chamberlain is a southpaw. That open-stance matchup makes foot position important, with both men looking to place the lead foot outside and open a path for the rear hand. Our guide to orthodox and southpaw boxing stances explains why that angle can shape an entire fight.
Chamberlain has the longer frame and the straight left to meet O’Leary on the way in. He does not always box tall, though. Against Rafferty, he was willing to stand close, trade hooks and work through contact. That toughness gives him options, but a long exchange may suit O’Leary more than a disciplined fight at range.
The champion is compact. He rolls forward behind the gloves, digs to the body and is good at turning a small opening into a sharp two or three-punch burst. His feet are not flashy, yet he rarely wastes movement. Once he reaches the right distance, he can keep an opponent busy without smothering his own work.
Much of the fight may come down to the first punch of each exchange. If Chamberlain lands the jab or straight left and pivots away, O’Leary will have to reset. If O’Leary gets his lead foot close enough to hook the body, Chamberlain could spend long spells fighting at the champion’s pace.
Why O’Leary Can Win
O’Leary is the steadier round winner. He keeps his shape, wastes little and has already proved he can carry a plan through 10 or 12 rounds. Home advantage helps, but his tactical discipline matters more.
The body should be a clear target. Chamberlain is tall for the matchup and can leave space below the elbows when he sets himself to punch. O’Leary’s left hook downstairs could slow the challenger and make the later rounds easier to control.
There is also a timing edge. O’Leary fought in March and came through without needing 12 punishing rounds. Chamberlain has been out since last August. A sharp start could put the challenger under scoreboard pressure before he settles.
Why Chamberlain Can Win
Chamberlain brings the more awkward geometry. His southpaw left hand travels straight towards O’Leary as the champion steps in, and his extra height should help him touch first if he maintains distance.
Power gives O’Leary something to think about as well. Chamberlain has stopped 12 opponents and dropped Rafferty during their title fight. Padley exposed him, but he has never been stopped and did not wilt in a far more frantic 12-round battle.
The crowd could become useful to the visitor if the fight stays close. Every O’Leary attack will produce noise, yet judges are supposed to reward clean, effective work rather than the reaction around it. Chamberlain does not need to silence the arena. He needs to make his counters obvious enough to stand out within it.
O’Leary vs Chamberlain Odds
BetVictor made O’Leary the 4/7 favourite in the fight-winner market on 27 July. Chamberlain was 5/4, with the draw at 12/1. Those prices show respect for the challenger; this is not being treated as a routine home defence.
Markets can move during fight week, particularly after the weigh-in. Check the latest winner, method, round and distance prices through BetVictor’s Boxing Betting & Odds page before placing a bet.
The outright market makes sense. O’Leary is unbeaten, active and fighting at home. Chamberlain, however, owns the higher stoppage rate and has already pushed an unbeaten domestic champion to a majority draw away from home.
Method of victory is less straightforward. Chamberlain has never been stopped, while O’Leary has never lost at all. A full 12 rounds therefore looks more plausible than either man being removed early. If backing a stoppage, check how the market groups knockout, technical knockout, retirement and disqualification. Our TKO vs KO guide covers the differences.
O’Leary vs Chamberlain Prediction
The pick is Pierce O’Leary to win on points.
Chamberlain can make this close. He has the length to interrupt O’Leary’s entries and enough power to discourage careless pressure. If the challenger controls the outside lane and finishes exchanges with the straight left, he can bank rounds without needing to dominate them.
I still trust O’Leary to solve the distance more consistently. His pressure is measured, his body work should reduce Chamberlain’s movement and he has shown a better habit of sticking to the same useful decisions from round to round. The longer the fight lasts, the more often he should reach the range he wants.
Do not expect a landslide. Chamberlain’s draw with Rafferty proved that he can absorb a hard pace and keep throwing in the championship rounds. O’Leary may have to win several tight sessions where two clean counters matter more than 30 seconds of aggression.
That is where judging becomes important. Our guide to boxing’s 10-point must system looks at how close rounds are assessed. I expect the cleaner body work and shorter combinations to give O’Leary the edge on all three cards, even if the scores do not fully show how competitive it felt.
Prediction: Pierce O’Leary by unanimous decision.
O’Leary vs Chamberlain Undercard
Royston Barney-Smith faces the experienced Reece Bellotti for the vacant IBO Intercontinental super-featherweight title in the chief support. Barney-Smith is unbeaten at 16-0 with eight stoppages. Bellotti brings a 20-7 record, 15 wins inside the distance and previous British and Commonwealth title experience.
Gary Cully meets Lee Reeves in an all-Irish super-lightweight contest. Cully is 19-2 with 10 stoppages, while Reeves arrives at 16-1 with 11. The winner can place himself close to the main-event conversation in a division full of domestic possibilities.
Another pair of Irish super-lightweights, Steven Cairns and Senan Kelly, meet over 10 rounds. Cairns is 14-0 and stopped Arnie Dawson in the ninth round at the same arena in March. Kelly stands at 12-1 and gets the chance to halt that momentum.
Unbeaten Ben Fail takes on Craig O’Brien at super-welterweight. Machlan Arthur, heavyweight Adam Olaniyan, Sean McComb and Bobbi Flood are also scheduled to appear, with opponents still to be confirmed at the time of writing.
All bouts and the running order remain subject to change.
What Could Be Next for the Winner?
Victory would carry O’Leary beyond the enjoyable part of his homecoming story. He has already held European and WBC International honours, and he has been ranked by major sanctioning bodies. Beating a live, dangerous challenger should move the conversation towards a final eliminator or a major-title opponent.
Dalton Smith holds the WBC belt at 140lb, while Britain’s domestic scene also contains names such as Adam Azim and Jack Rafferty. None should be presented as a signed next fight, but the winner in Dublin will have several credible routes.
For Chamberlain, an away victory would repair the Padley defeat in one night. It would also settle the unfinished business left by the Rafferty draw and give him a belt with which to demand another headline fight.
For O’Leary, the dream is larger. He has spoken about leading the next wave of Irish boxing and eventually reaching Croke Park. Those ambitions require more than popularity. First, he has to beat the southpaw who has spent months insisting that Dublin’s noise will not matter.
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