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Mikaela Mayer Dominates Mary Spencer to Become Unified Champion at 154 Pounds

Originally posted on Dice City Sports | By Robert LaMar | Last updated Oct 31, 2025 11:23 AM ET

MONTREAL — Mikaela Mayer is back on top and now, she’s a unified champion in a third weight division. The former two-division world champion produced a masterful performance Thursday night, defeating WBA champion Mary Spencer by unanimous decision to claim both the vacant WBC and WBO junior middleweight titles. The fight headlined a Top Rank card at Casino de Montreal, where Mayer’s relentless pace and precise pressure overwhelmed the hometown favorite across ten one-sided rounds.

A statement win for Mayer

Mayer (22-2, 5 KOs) took command from the opening bell, using her signature jab and superior conditioning to walk down Spencer (10-3, 6 KOs) throughout the fight. Judges scored the bout 100-90, 98-92, and 98-92, all in favor of Mayer, who barely allowed Spencer a moment to breathe.

Spencer, 40, entered the fight as the naturally larger woman, but she struggled to impose that physical advantage. Instead, she found herself fighting off the back foot, repeatedly tagged by Mayer’s straight right hands and combinations.

By the eighth round, Mayer’s consistent pressure began to wear Spencer down. A crisp right hand visibly staggered the Canadian, and Mayer closed strong, battering her opponent with a barrage of clean shots until the final bell.

Mikaela Mayer beats Mary Spencer to become the unified super-welterweight world champion

Mayer becomes champion in a third weight class pic.twitter.com/yvroGWYeys

— Ring Magazine (@ringmagazine) October 31, 2025

“I have options now,” says Mayer

For Mayer, 35, this victory represents both vindication and evolution. After a turbulent two-year stretch including a narrow loss to Alycia Baumgardner in 2022 and a close decision defeat to Natasha Jonas at welterweight Mayer has once again found her championship groove.

“I think the most important thing is that I have options,” Mayer said post-fight. “I cleared my head after a tough two years. I’d love to do both go down to 147 to become undisputed and defend at 154. I think I’m a natural 147-pounder. I can do both.”

Mayer previously held unified titles at super featherweight (130 lbs) and later won a world title at welterweight (147 lbs) after defeating Sandy Ryan in 2024. Thursday’s triumph now makes her a unified champion in yet another division solidifying her as one of the most accomplished women in modern boxing.

The path ahead: Undisputed ambitions

With the IBF title currently held by Oshae Jones, Mayer has a clear path to undisputed status at 154 pounds. Alternatively, a return to 147 could set up marquee matchups with three-belt champion Lauren Price or a rematch with Jonas.

Regardless of which direction she takes, Mayer’s resurgence is undeniable. Once again, she’s proving that weight, age, and setbacks are no barriers for one of boxing’s most disciplined and determined champions.

This article first appeared on Dice City Sports and was syndicated with permission.

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