Mikaela Mayer became unified super-welterweight champion with a dominant unanimous-decision victory over WBA champion Mary Spencer in Montreal to claim the vacant WBC and WBO belts.
Former two-division champion Mayer (22-2) applied relentless pressure from the opening bell to overwhelm Spencer (10-3), who struggled to counter despite her size advantage as one judge scored it 100-90 and the other two had it 98-92 for Mayer.
With the IBF title held by Oshae Jones, Mayer could now pursue undisputed status at 154 pounds or return to welterweight to challenge three-belt champion Lauren Price.
“I think the most important thing is that I have options,” Mayer said.
“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.”
After starting her career 17-0 and unifying the super-featherweight division, Mayer lost a close decision to Alycia Baumgardner in 2022.
Mayer lands a blow to Spencer
She rebounded with two lightweight wins in 2023, then fell short against Natasha Jonas in her first welterweight title bid.
Mayer later captured the WBO welterweight title by defeating Sandy Ryan in 2024 and defended it successfully in their March 2025 rematch.
Moving up again, Mayer was expected to struggle with the larger Spencer but instead imposed her will, working behind a sharp jab and constant forward motion.
Spencer, 40, had her best moment in the fifth round with a clean uppercut, but Mayer’s chin held firm.
