Briton Savannah Marshall will challenge Claressa Shields for the undisputed middleweight championship at the O2 Arena in London on 10 September.

Like Shields, Marshall is undefeated in 12 pro fights, but has 10 knockouts.

“What she’d done for the sport is amazing,” said Marshall, 31. “She’s a pioneer, but the reality is she doesn’t beat me.”

In a heated media conference in central London, the 27-year-old Shields said: “I hate nobody but I really do have a huge dislike for her.”

In the first all-female card to be hosted in the United Kingdom, Mikaela Mayer will face Alycia Baumgardner in a super-featherweight unification clash.

Mayer is the WBO and IBF champion, while fellow American Baumgardner holds the WBC belt.

A fight 10 years in the making

The undisputed clash between Marshall and Shields is a fight 10 years in the making.

“I’m not going to just beat you. I’m going to outbox you. I’m going to hurt you and outbox you,” Marshall told her opponent.

The fight was delayed in May because of an injury in Marshall and will now go ahead in London rather than the original planned location of Newcastle.

Shields’ only defeat in her entire boxing career was against Marshall as an amateur when they were both preparing for the 2012 Olympics – a Games at which Shields would win a gold medal and Marshall would bow out at the quarter-final stage.

The duo never fought again in the ring but have sparred together on occasion. Both have their own version of how those sparring sessions went, but the defeat to Marshall when she was 17 has been a constant sore spot for Shields.

“Marshall got lucky in 2012, but she won’t get lucky in 2022,” added Shields, who describes herself as the Greatest Woman of All Time (GWOAT).

“They’re saying she’s a big knockout puncher, the only blemish on my record as an amateur…she has the recipe to beat me.

“My job is to show everybody in the world she doesn’t. I don’t reign supreme in three different weight classes for no reason.”

The American has developed into a wonderful fighter since they last met, winning world titles at multiple weights. She also became the first boxer – male or female – to hold two undisputed championships in two weight divisions at the same time.

Shields is a two-time Olympic champion and returns to fight in London for the first time since winning gold at the 2012 Olympics.

Marshall’s career at amateur level never reached the heights it promised, but the Hartlepool-born fighter’s pro career has gone from strength to strength in the last two years.

She is now billed as one of the biggest punchers in women’s boxing with 10 knockouts and will be aiming to secure her ninth stoppage in a row when she faces Shields.

“This fight has been a long long time coming,” Marshall added. “We’re here now.

“I win this fight through heart and my boxing brain. My boxing brain wins me this fight.

“On September 10 I will become undisputed champion – and that will be the end of all this GWOAT rubbish.”

A historic night for women’s boxing

The Mayer-Baumgardner contest is one whereby the winner could set up an undisputed clash against South Korea’s WBA title-holder Hyun Mi Choi.

Mayer, who has won all 17 professional bouts, is a 2016 Rio Olympian who won the WBO belt in October 2020. Eight months later, she added the IBF and Ring Magazine straps by defeating Argentine Erica Fari.

Baumgardner, who has won 13 and lost one, defeated Doncaster’s Terri Harper to claim the WBC super-featherweight title in November last year and has made one defence of the belt.

‘September 10 is going to be special’ – analysis

BBC Sport’s boxing reporter Kal Sajad at the media conference:

Finally, the long-time rivals will get it on again. This time as professionals on what will be a historic night for British and women’s boxing. It will be the first female fight to headline the O2 Arena.

There was a huge buzz at the media conference. The fighters made their way down the lavish stairs at Banking Hall in central London.

With the flags of their respective countries draped in the background, they went head-to-head, but it was only when they took their seats that the true fireworks started as a shouting match ensued.

Marshall goes by the alias ‘The Silent Assassin’, but that may need updating – she is not as shy as she once was. Whenever a pumped-up Shields raised her voice, Marshall grinned and held her own in response. Perhaps ‘The Smiling Assassin’ is a better fit.

Any athlete who describes themselves as the ‘GWOAT’ is bound to be divide opinion.

Shields’ confidence is often perceived as arrogance, particularly by British fight fans, but her achievements in the sport are truly magnificent.

If she can avenge the one loss on her record, her standing as the very best may get the seal of approval from boxing aficionados.

Credit must go to Ben Shalom and Boxxer for once again being able to deliver a huge grudge match. The relative newbies of British boxing did it with Amir Khan-Kell Brook in February and have done so here too.

The bad blood between the pair has been well documented, but when you strip it all back you are left with two magnificent competitors. The puncher versus the boxer, two amateur stars who excelled in the professional ranks.

The addition of Mayer-Baumgardner to the bill is huge. We have two of the biggest women’s bouts in world boxing on an all-female card and events like this can often leave a legacy and go a long way to helping the sport grow.

After the success of Katie Taylor v Amanda Serrano in May – a fight which headlined and sold out the iconic Madison Square Garden – we can say with certainty that 2022 is a game-changing year for women’s boxing.

Saturday 10 September is going to be special.