LAS VEGAS — It's rather poetic that Armando Resendiz's nickname, “El Toro,” is the same as the late great Los Angeles Dodgers hero Fernando Valenzuela, who took baseball by storm as an unknown Mexican rookie pitcher to win league awards and a championship in 1981 en route to creating Fernandomania.

On Saturday night, the little-known Mexican super middleweight and massive underdog Resendiz shocked the boxing world by bull rushing and beating Caleb Plant by decision.

The bout was designed to be a tune-up for Plant, just as Jermall Charlo had in his stoppage win in the co-feature against Thomas LaManna, so the stars could face each other. But a resounding performance by Resendiz disrupted such plans and proved that fights are not won on paper.

As Resendiz (16-2, 11 KOs) left the tunnels of the Michelob Ultra Arena and headed into Mandalay Bay, the newly minted WBA interim champion was mobbed by family and a swarm of newfound fervent followers.

A swell slowly started to build as fans flocked for photos and celebrated by singing in Spanish. Premier Boxing Champions apparel merchandiser David Goldfarb broke open already packed boxes of shirts and hoodies for people looking to get their hands on a last-minute relic to commemorate the occasion. One person even took off his shoe to get it signed by Resendiz.

Suddenly, a fever pitch of Armandomania struck the casino floor, and the sights and sounds were clear — a fresh face for Mexican boxing had emerged.

"I'm so happy and beyond thankful,” Resendiz said through a translator. "I fought many battles, and now I am here. I couldn't be more thrilled with how things turned out. It was the confidence I had in my skills and myself to have serenity and not listen to the outside noise."

While Plant (23-3, 14 KOs) proclaimed throughout the promotion that Resendiz would get stepped on, the genial underdog, who looks more like actor and boxing super fan Mario Lopez's twin than Valenzuela, was all smiles and as loose as can be throughout fight week.

"This upset belongs to my entire team," said Resendiz. "We had more than one strategy as a team. It wasn't just Plan A. I stayed true, listening to my corner. The way we interacted was a key to the victory. We saw the fruits of that labor coming through, and we didn't stop. I perhaps could have done more."

Although Resendiz outfoxed, outhustled, and outmuscled Plant and outlanded him 186-108 while dominating the second half of the fight, judge David Sutherland surprisingly scored it 115-113 for Plant.

Plant thought he did enough to win the fight, but judges Max De Luca and Steve Weisfeld each correctly scored the contest 116-112 for Resendiz.

The sport is strewn with bones of hard-luck B-side fighters such as Resendiz who get robbed and rarely recover. For the soon-to-be-father Resendiz, a resurgence is now in store as a top player in a stacked division, and he officially holds a lottery ticket looking for his number to be called against undisputed king Canelo Alvarez.

Resendiz, a 26-year-old from Guayabitos, Nayarit, turned pro in 2018 and fought exclusively in Mexico until moving his campaign to the United States in 2021. In his second stateside fight, he got dropped en route to his first career loss to unheralded contender Marcos Hernandez.

After stopping a faded version of former unified junior middleweight champion Jarrett Hurd in 2023, Resendiz was stopped by Elijah Garcia months later and his career potential came into question. After a 17-month break, a tune-up February win in Mexico led him to the former titleholder Plant, who came in as a minus-2500 betting favorite and ranked by The Ring as the world's fourth-best super middleweight.

And on the eve of the sixth anniversary of Andy Ruiz Jr. knocking out Anthony Joshua to become the first ever heavyweight champion of Mexican heritage, Resendiz pulled off the Upset of the Year frontrunner while guided by Ruiz's coach, Manny Robles.

"This is definitely a huge upset and an all-time one that makes me proud," said Robles. "I was talking to Armando a year ago, telling him don't ever give up, and that good things were going to come his way. Armando persevered like the best of them, and look at where we are now."