Claressa Shields appreciates how far women’s boxing has come since she turned pro almost six years ago.

Back then, an enormous moment like the one that awaits her Saturday night in London didn’t seem possible. Even Shields’ staunchest supporters tried to brace her for the potential disappointments she was sure to encounter in the male-dominated boxing business.

The 27-year-old Shields realizes there remains plenty of progress to make, but the undefeated three-division champion has taken time to notice what her middleweight championship showdown with Savannah Marshall means to women’s boxing as a whole, not just to her career.

“To be at the O2 Arena, main event, I think it’s the first women’s fight to be the main event at the O2 Arena, it’s huge,” Shields told BoxingScene.com. “And I’m super happy about it. Since I turned pro, I knew I was the woman to be the one to change the fight game. You know, and I was telling some of the people I love and who was close to me in the fight game, ‘Look, I’m the one.’

“And they were like, ‘As great as you are, we don’t want you to get your hopes up because there may not be any respect or any money for you in boxing. We know that you feel this, but we just want to get you mentally prepared. Not to say that we told you so, but just like, hey, you might not get what you want.’ But deep down in my heart, I knew that I was the one, that I would get what I want and that I would be a trailblazer in boxing.’ ”

An appreciative Shields sat ringside, as an analyst for DAZN, when Katie Taylor and Amanda Serrano drew a crowd of 19,187 to Madison Square Garden for a fantastic lightweight title fight Taylor won by split decision April 30 in New York.

The two-time Olympic gold medalist also is proud that one of her longtime USA Boxing teammates, Mikaela Mayer, will square off against Alycia Baumgardner in the co-feature Saturday night. The biggest fight of Mayer’s career will afford her the opportunity to add two more 130-pound championships to her collection.

“Katie Taylor, Amanda Serrano and myself, Mikaela Mayer, we all added to the game in our own way,” Shields said. “But I’ve always been one to speak up for equal pay. I’ve always been one to speak up for equal fight time, equal promotions and equal everything, equal buildup. So, I’m happy I’ve done my work, but there’s still more work to be done. I’m happy women’s boxing is here because it went from nothing to something huge. And I’m a part of that something huge.”

The 10-round, 160-pound battle between Shields (12-0, 2 KOs), of Flint, Michigan, and Marshall (12-0, 10 KOs), of Hartlepool, England, will headline an all-women’s show that’ll be broadcast by Sky Sports in the United Kingdom and Ireland (7:30 p.m. BST) and streamed by ESPN+ in the United States (2:30 p.m. ET). The odds on the Shields-Marshall match are approximately even, according to most sportsbooks.

Mayer (17-0, 5 KOs), of Colorado Springs, Colorado, is consistently listed as a more than a 2-1 favorite to beat Baumgardner (12-1, 7 KOs), of Bingham Farms, Michigan. Baumgardner and Mayer will fight for Baumgardner’s WBC and IBO belts and Mayer’s IBF and WBO championships.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.