Chantelle Cameron produced one of the finest displays of her career to beat Mikaela Mayer and add the WBA and WBC light middleweight titles to her WBO belt.
An engrossing encounter was narrowly won by the British fighter by unanimous decision - 97-93 on two scorecards and 96-94 on the other.
American Mayer disagreed with the decision, claiming she "outboxed" Cameron – leading to an angry exchange of words in the ring.
The possibility of a rematch was also floated, with Mayer also suggesting Cameron had benefited from home advantage – to the champion's chagrin, as she said "talk is cheap".
It means Cameron remains unbeaten since her second fight with Katie Taylor in 2023, and with 23 victories in 24 professional encounters.
And this was one of her best displays. These fighters were evenly matched in every metric – from punch rate to height and weight, even hairstyle.
But Cameron won out thanks to her unrelenting pressure, which never allowed the usually adaptable Mayer to figure out a winning gameplan.
Mayer was the more imposing figure early on, but Cameron played counterpuncher until she could get onto the front foot.
Cameron forced Mayer against the ropes in round four, and again at the start of the fifth. Increasingly confident to take the initiative, she was roared on by a partisan but disappointingly small home crowd.
Mayer was unable to get in behind her jab for long periods and was bleeding and breathing heavily by round six.
The home favourite was cut in the final rounds but pushed through and was lifted shoulder high by her team before her biggest win since beating Taylor in Dublin three years ago was announced.
For three-weight world champion Mayer, this is the third defeat of her 25-fight career and costs her the WBA and WBC belts, which Cameron now puts with her WBO title.
From influencers to queens of women's boxing - five years of MVP
However, the elevation of Moses Itauma v Filip Hrgovic to a world title fight left this big-ticket event feeling rather undeservedly like a support act.
That was reflected in the crowd, with scores of empty seats around the arena as the main undercard began. At a generous estimate, BP Pulse Arena was half-full when the fighters made their ring walks for the main event.
Mayer and Cameron did their best to bring the big fight feeling in the build-up. Previously cordial relations boiled over on Friday as they butted heads at Friday's weigh-in at BP Pulse Arena.
Cameron shoved her head into the American, who pushed back, before they exchanged insults side by side.
On fight night, Mayer played up her away status by entering the ring to American Woman by Lenny Kravitz. She also wore a black durag over her trademark blonde hair, before removing it to show tight dreadlocks – the same style as Cameron.
However, her moxie was eventually worn down by Cameron, with a big right to the chin in round seven the most notable of blows.
This fight headlined the event marking the fifth anniversary of Most Valuable Promotions (MVP), the promoters fronted by Jake Paul who, since 2021, have moved from YouTuber fights to leading the way for women's boxing in the UK.
Paul, influencer and co-founder of MVP, was in the house. He headlined on 29 August 2021, beating MMA fighter Tyron Woodley, but was in a watching brief here.
MVP's next women's boxing arena event will take place in November in Texas.
It will be headlined by unified super-featherweight champion Alycia Baumgardner, with the American stepping up to lightweight to face Elif Nur Turhan – on her way to a potential 2027 showdown versus Caroline Dubois.
World championship fights on the undercard will include featherweight champion Tiara Brown defending against former undisputed champion Ellie Scotney, and super bantamweight champion Skye Nicolson against three-time, two-division champion Miyo Yoshida.
The next fight is particularly important for Cameron, after her first fight at BP Pulse Arena since November 2024 – and her first since her much-lauded move to MVP.
MVP have plenty of options they could introduce from their stable. IBF light middleweight champion Oshae Jones seems the logical next step; or IBF, WBO and The Ring middleweight belt holder Tammara Thibeault of Canada.
Cameron regularly laments that she has not had the chances her talent deserves since her blockbuster double header against Taylor in 2023.
Three years on, she will want fights of that level – especially after Saturday night's result.
Notifications, social media and more with BBC Sport
