LAS VEGAS – As soon as Spanish singer Leiva’s guitar strummed starting Isaac “Pitbull” Cruz’s walk-in, something about boxing changed.

The crowd went wild, a transforming 140-pound title victory over Rolly Romero seemed imminent and Mexico delivered the sport its latest champion from Central Casting.

“Think about it,” Cruz’s enthusiastic manager Sean Gibbons urged. “There’s Canelo. And there’s ‘Pitbull.’”

Cruz’s relentless, vicious attack wobbled Romero (15-2) early, left him on shaky feet and inhibited during the bout and set up a destructive eighth-round TKO that made Cruz – a third-generation boxer – the WBA super-lightweight champion.

"I was prepared for this. I wasn't here to just fight. I was here to terminate him,” Cruz said in the ring afterward. “There's going to be a Mexican champ at 140 pounds for a long time.”

That’s saying something given the depth of a division that boasts Devin Haney, Subriel Matias, Teofimo Lopez and Gervonta “Tank” Davis as current or recent champions.

Sure, Cruz (26-2-1, 18 KOs) lost to Davis after stepping in as a replacement fighter in 2021, but look at what he did off a full training camp Saturday, look at how his now thunderous fan base boosts his value and look at his new strap.

“It made no sense for Gervonta to fight ‘Pitbull’ Cruz until he had a belt,” Gibbons said. “Now, he has a belt. We’re not calling ‘Tank’ out. We’re not chasing him.

“People keep asking me about Gervonta Davis. It’s not about Gervonta Davis. We don’t need him in the sense that if he doesn’t want to fight … you heard this place … (Cruz) can main event on his own. If Gervonta wants to do it next, great. If not, we’ll figure out a fun defense and what to do. We know he can headline this building (T-Mobile Arena) himself. That’s what he did tonight, with 14,726 in the building.”

While Davis is pointed to a June 15 main event in Las Vegas against lightweight foe Frank Martin, Gibbons wants Cruz to return to the ring in August or September and then fight again by year’s end.

How willing is he to participate in a round-robin with the rest of the champions, after Haney fights return challenger Ryan Garcia April 20, after Matias fights June 15, and Lopez defends his belt June 29?

“You know the business. You know the promoters. You know who Teofimo is with (Bob Arum), you know who Subriel Matias is with (Eddie Hearn), you know who Devin Haney is with (himself),” Gibbons said.

“If Ryan Garcia wins, that’s the fight. If Gervonta Davis wins, that’s the fight. Those are the easiest fights to make. The other ones … Matias would be bombs away. Devin Haney’s a fantastic fighter, but who wants to watch him try to outbox ‘Pitbull?’ We want guys who come to fight. Rolly didn’t come to fight. You saw it. After he got hit, the bicycle was going.”

More than that, Cruz seized his moment, flashing all of his development from a four-month camp and bringing glory to his grandfather, Memo, who started boxing in 1966 and went on to defeat Pipino Cuevas before leaving the sport belt-less along with Cruz’s father-trainer, who retired with ‘Pitbull’ as a toddler.

“It means so much to me, to be able to enjoy this with my grandpa and my dad while both are still alive,” Cruz said with the belt on his lap at the post-fight news conference. “The fact I can carry that mantle and achieve what, unfortunately, they were unable to achieve, to take it and reach the top … that’s priceless to me.”

Gibbons basked in ‘Pitbull’s display: that fierce glare, shoulders like a linebacker, the stone-cold demeanor in the ring.

“He is a Mexican Mike Tyson. Every punch is with bad intentions. He doesn’t jab very often. He knows what he’s doing. He’s not just out there wingin’. He does things with reason,” Gibbons said.

“I would say a star was born. (PBC head) Al Haymon saw this tonight. The first PBC on Prime Video fight captured it. It’s so refreshing.”