Mikaela Mayer has secured world titles at 130-pound, 147-pound, and now light-middleweight divisions.
The American boxer defeated Mary Spencer in Montreal to claim the combined 154-pound title and become a three-division global titleholder.
This veteran American delivered a dominant performance at the Montreal Casino, outmaneuvering the hometown favourite over 10 rounds.
Officials scored the bout 100-90, 98-92 and 98-92 as the champion secured the WBA crown and the vacant WBC and WBO belts.
"I've won a World Boxing Organization title previously, but this is my first time with the WBA or WBC strapped around my waist, so it feels extra special," she remarked.
The fighter, who is also the reigning WBO titleholder at welterweight, won her first world title at 130 pounds. Her record now stands at 22 victories and two losses.
Fight Breakdown
The Californian quickly settled into her groove behind a sharp jab, varying her attacks to head and body.
Despite giving up two inches to the taller Spencer, she commanded the range and tempo for the entire fight.
Spencer, 40, had brief success in the fourth stanza when a couple of right hands landed, but the American reasserted herself, closing the eighth round with multiple strong punches and a wide points victory appeared inevitable.
Spencer was bloodied and marked under both eyes at the final bell as the Canadian suffered a third defeat in 13 fights.
"She's a tough, durable opponent. Props to her, she didn't have to accept this bout," Mayer commented. "She accepted a major gamble facing a boxer of my caliber. I always come forward and deliver tough fights."
What's Next?
Mayer's only two professional losses came by narrow judges' decision - to Alycia Baumgardner in 2022 and another in 2024.
The champion restated her career ambition of achieving an undisputed champion after a second consecutive win.
She had hoped to meet the Welsh Lauren Price, the WBC titleholder, in an undisputed fight.
That bout fell through mainly because of promotional and broadcast issues.
Should a bout with Price - who is scheduled to be returning in the UK in December - fails to happen for the American, she could pursue complete unification at 154 pounds against IBF titleholder Oshae Jones.
"The most important thing is that I can choose," Mayer stated.
"I want to do both - return to welterweight for undisputed, then move up and retain at 154lb."
A possible mega-bout may also emerge on the cards against a renowned champion, the self-proclaimed 'Greatest Woman of All Time' and fully unified three-weight world champion, who presently owns titles at heavyweight.
American Shields, presently a unattached boxer, is drawing offers from several promoters, including Most Valuable Promotions.
Should she were to move down to super-middleweight, the American - despite it not being a natural weight - has stated she would happily face her there.
