Sebastian Fundora didn’t show any signs of ring rust Saturday night.

“The Towering Inferno” ended a layoff that lasted almost one year by stopping Chordale Booker in the fourth round of this battle between southpaws at Mandalay Bay Resort and Casino’s Michelob ULTRA Arena. The 6-foot-6 Fundora dropped Booker after landing two vicious uppercuts, which eventually led referee Thomas Taylor to spare the 33-year-old Booker from taking unnecessary punishment.

The 5-foot-9 Booker was on his feet when Taylor stopped their scheduled 12-round, 154-pound championship match at 2:51 of the fourth round. The heavily favored Fundora (22-1-1, 14 KOs), of Coachella, California, retained his WBC and WBO belts by winning the main event of a tripleheader streamed by Amazon’s Prime Video.

“I’ve felt ready this whole time since my last fight,” Fundora said. “I’ve worked very hard this past year to be ready. Now I’ve successfully defended my two titles and the sky’s the limit. … I showed the fans that I’m a powerful fighter. I’ve always been a powerful fighter and I showed it even more tonight.”

Fundora, 27, fought for the first time since he upset Tim Tszyu by split decision last March 30 at nearby T-Mobile Arena. Australia’s Tszyu (24-2, 17 KOs) suffered a grotesque gash near the middle of his hairline at the end of the second round and bled badly throughout what was still a very competitive bout.

The taller, sharper, stronger Fundora, The Ring’s fifth-ranked junior middleweight, had no such issues Saturday night.

“We didn’t even bring a southpaw into camp,” Fundora said. “It was just about catching his footwork. He didn’t want to trade at all, so we just broke him down to the body and when I hurt him in the third round, it slowed him down a lot.”

Booker (23-2, 11 KOs), whose six-fight winning streak ended, lost inside the distance for the second time in nine years as a pro. Another southpaw, Austin “Ammo” Williams, stopped the Stamford, Connecticut native in the first round of their April 2022 bout at Madison Square Garden in New York.

Almost three years later, Fundora staggered Booker with a left uppercut, which made him move into the ropes with about 50 seconds to go in the fourth round. Two more left uppercuts by Fundora wobbled Booker and made him lose his equilibrium.

The challenger went down with just under 40 seconds remaining in the fourth round. Booker beat Taylor’s count, but he didn’t last much longer.

An aggressive Fundora, who was a 14-1 favorite according to DraftKings, realized the end was near and unloaded a barrage of power punches on Booker, whose back was against the ropes. Taylor moved between them

Booker landed to Fundora’s head and body in the third round, but none of his punches appeared to affect Fundora. The champion continued to press the action throughout that round and landed a left uppercut that caused Booker to hold him with under 40 seconds on the clock.

Taylor called for a break in the action with just over 1:20 to go in the second round because Fundora hit Booker on the back of his head. Booker shook it off – literally – and the action resumed once Taylor warned Fundora.

A straight left by Fundora made Booker reset his feet just after the halfway point of the first round. Barely 10 seconds later, Booker connected with a right hook as Fundora came forward.

Fundora’s consistent jab primarily won him the opening round. Once he started connecting with uppercuts, Fundora’s focus shifted toward potential fights in the 154-pound division later this year.

“I’d love to be the undisputed champion, like my sister,” Fundora said in reference to 22-year-old Gabriela Fundora, the undisputed women’s flyweight champion. “Whoever they have for me next, I’ll be ready. I want the IBF champion Bakhram Murtazaliev, plus Xander Zayas is the WBO mandatory, and I also want Errol Spence Jr. We have two belts, we have to defend them, and if anyone is willing to unify, let’s do that, too.”