Mikaela Mayer-Sandy Ryan rivalry explained: All you need to know

In less than a year, Mikaela Mayer and Sandy Ryan have developed perhaps the most vicious and acrimonious rivalry in the history of women's boxing. Insults hurled back and forth both before and after their fight last September, and a debatable judges' decision in that fight, lead us to Saturday's rematch at Fontainebleau Las Vegas.

And don't forget that Ryan suffered an attack on her way to Madison Square Garden for the first fight. Leaving her New York hotel, she was struck by a can of red paint by someone on the street. Ryan has blamed Mayer and her team, something they have denied.

There's also the issue of coaches. "Coach Kay" -- Kay Koroma, who trained Mayer for most of her career -- moved on to coach Ryan for her fight against Mayer, and will be in Ryan's corner again this weekend.

Mayer (20-2, 5 KOs), a 34-year-old American, will be making a first defense of the WBO welterweight title after an eventful first fight ended with her taking a majority decision (95-95, 97-93, 96-94) over Ryan (7-2-1, 3 KOs), 31 and from England. Here's how we got to this point in a festering feud.

Jan. 24, 2024: Mayer, from Colorado but based in Las Vegas, makes an impressive debut at welterweight but loses a split decision to Natasha Jonas in Liverpool, England. Mayer calls for an immediate rematch.

Mayer, who reigned as unified junior lightweight champion for two years until she was beaten by Alycia Baumgardner in 2022, does not get the rematch, but her strong performance after stepping up in weight to take on Jonas puts her on the radar of the other leading welterweights.

March 24, 2024: Ryan, from Derby, puts herself on a collision course with Mayer by defending her WBO welterweight title with a fine four-round stoppage win over Terri Harper. The career-best win cements Ryan as one of the leading figures at welterweight.

Afterward, Ryan calls out Jonas and Chantelle Cameron, her English rivals, but they have other plans. Ryan wants a big name next, but who is available? A rivalry with Mayer has been brewing behind the scenes and is about to explode.

June 26, 2024: Mayer claims on social media that Ryan turned down an offer to fight her. Ryan replies on social media: "I'll fight you any time and any day of the week drama queen. But when the offer was terrible for me to defend my belt and you come with nothing I was advised differently by my team."

The bad feeling emanates from Ryan's move to train with coaches who were working with Mayer. Ryan started working with trainers Kay Koroma and Flick Savoy following her draw with Jessica McCaskill in September 2023, and that upset Mayer. The American had been training with Koroma for eight years and felt there was a conflict of interest since she was looking to move up to welterweight. So Mayer left Koroma to train with Kofi Jantuah following her defeat to Jonas. A few weeks after the online exchange, Ryan vs. Mayer is announced for Sept. 27.

Sept. 26, 2024: During fight week, Koroma's name inevitably comes up in spiteful exchanges at media events.

Mayer: "You knew I was coming to 147 pounds, why would you move to America and start training under my team? That doesn't make any sense."

Ryan calls Mayer a "trashy woman" after a faceoff in which Mayer raised her middle finger.

Sept. 27, 2024: Before even arriving at Madison Square Garden for the fight, Ryan feels under siege. As she leaves her New York hotel, Ryan is struck by a can of paint, leaving her splattered in red.

An emotional and shaken Ryan sits down with ESPN's Mark Kriegel after arriving at the Garden and says, "I left my hotel room to meet my team downstairs and there were cars waiting for us to get in and I was about to get in the car when something smashed me in the stomach.

"When I looked down, it was a tin of paint. Looked up, and a guy with a hood up, running, jumped into a car and they drove off. Hit and run."

Ryan believes she knows who is behind the attack. "Mikaela Mayer is definitely getting it," she tells ESPN. "It's definitely a setup from her team. Who knew what time I was coming out [of] the hotel? I've stayed calm all week, and they are still trying to make a way to ruin my mindset."

Later in the evening, the fight itself is brilliant, a relentless scrap. Both fighters have good moments. In the opening round, Mayer shakes Ryan with a huge right hand. Round 3 is intensely toe-to-toe. As the fight goes on, Mayer lands some sharp combinations and Ryan heavy left hooks. Mayer has more success in Round 10, and her combinations and strong finish perhaps make the difference on the scorecards. According to CompuBox statistics, Mayer lands 41% of her power punches compared to Ryan's 37%. But the story of the fight is as much about what happened before they got in the ring as it is about the entertaining 10 rounds.

Sept. 30, 2024: Ryan releases a statement saying the paint attack was not the only thing she had to contend with on the day of the fight.

"Obviously, the paint attack has received a lot of coverage, but I was also subjected to a disgusting and pathetic smear campaign on fight day where hundreds of leaflets featuring my image and defamatory text were distributed and posted on the streets surrounding my hotel and Madison Square Garden both before and after the fight," Ryan wrote in that statement.

"ESPN had me winning by two rounds [ESPN's Kriegel scored it 96-94 in favor of Ryan] and I know many other respected boxing observers also had me winning the fight. In light of everything that's happened, I believe that an immediate rematch should be ordered.

"Boxing deserves so much more than this kind of thuggery."

Mayer's agent, George Ruiz, denies the claim that Mayer's team was behind any of it, addressing Ryan directly: "Let me be clear: No one associated with Team Mayer had anything to do with the paint assault on you or the leaflets and the alleged anonymous threatening messages you say you received."

Dec. 28, 2024: Ryan releases CCTV footage of the paint attack on her social media channel.

The video shows an unidentified person getting out from behind the driver seat of an SUV parked outside the hotel and walking slowly toward Ryan, carrying an object in the right hand, then throwing that object at Ryan before running back to the car.

Jan. 30, 2025: The rematch is announced, and Ryan says it will be a different fight this time. "After what happened before the fight last time, I did fight in anger and it clearly affected my performance," she says.

Feb. 5, 2025: The bickering continues on "The Ariel Helwani Show." "You don't like me because I've called you out on your s---" Mayer says. "You're the one who came into my country and tried to train with my team, even sent me a letter saying, 'I'm so sorry'..."

Ryan says again she underperformed in the first fight because she was affected by the prefight assault.

"She thinks I'm mentally broken, mentally weak, and all that," Ryan said.

"We'll see who's going to be the broken one after this fight. I believe I will stop it this time. I wasn't sitting down on my shots because I was fighting on emotion and anger. Let's see if she can take the shots when I connect clean this time."

Feb. 16, 2025: Mayer suggests it could have been a fan who carried out the paint attack.

She tells UK radio station talkSPORT: "Rumour is that Sandy is not a very likeable person in her hometown, which is probably why she is out here on my turf trying to find a team because she can't find one back home. Maybe it was someone who just despises Sandy. ... It could very easily have been a fan."

March 9, 2025: Despite the controversy around the first Ryan fight and her intense rivalry with the Englishwoman, Mayer is named the British Boxing Board of Control's Overseas Boxer of the Year.