Jermell Charlo stops Brian Castano to become undisputed super welterweight champion

American adds Argentine's WBO belt to his WBC, WBA, and IBF straps following 10th-round knockout

Jermell Charlo reacts after knocking out Brian Castano during their undisputed super welterweight fight at the Dignity Health Sports Park in Carson, California, USA on May 14 2022. EPA

Jermell Charlo throws a punch at Brian Castano during their undisputed super welterweight fight. EPA

Brian Castano and Jermell Charlo during their undisputed super welterweight fight. EPA

Jermell Charlo throws a left hook at Brian Castano during their undisputed super welterweight fight. EPA

Jermell Charlo celebrates his knockout victory over Brian Castano. EPA

Brian Castano and Jermell Charlo exchange punches. EPA

Jermell Charlo and Brian Castano during their undisputed super welterweight fight. EPA

Jermell Charlo in action against Brian Castano at the Dignity Health Sports Park in Carson, California. EPA

Jermell Charlo throws a body shot at Brian Castano during their undisputed super welterweight fight. EPA

Jermell Charlo, right, celebrates after defeating Brian Castano in a super welterweight boxing title bout Saturday, May 14, 2022, in Carson, Calif. (AP Photo / Marcio Jose Sanchez)

Jermell Charlo became the first first undisputed super welterweight champion in history on Saturday after knocking out Brian Castano in the 10th round of a thrilling fight in Los Angeles.

Charlo, the reigning WBC, WBA and IBF champion, earned Castano's WBO belt with the win at the open-air Dignity Health Sports Park arena. The American fought to a controversial draw against Castano last year.

The 31-year-old Charlo sent Castano to the canvas twice in the 10th round just as he had begun to get on top of a hard-fought battle that saw the two men share the opening rounds.

A crunching right hook to the body stunned Castano and Charlo followed with a left hook to the head that sent the previously undefeated Argentinian crumpling to the canvas.

With Castano unsteady on his feet, Charlo moved in to finish his opponent. A powerful left snapped Castano's head back and another punishing left to the body sent him to the deck for the final time.

"This is unbelievable," said Charlo, who improves to 35-1-1 (19 knockouts). "I gave it my all and that was the end result of it. This was nerve-wracking. It felt like my first fight, where you get nervous. I knew Castano was going to give it his all, and I trained very hard. I was in great shape."

Charlo's win elevates him to an exclusive club of fighters. He is only the seventh boxer to hold all four belts from the major sanctioning bodies – WBC, WBA, IBF and WBO – at the same time.

The six men to do it before are Bernard Hopkins (middleweight), Jermain Taylor (middleweight), Terence Crawford (super lightweight), Oleksandr Usyk (cruiserweight), Josh Taylor (super lightweight), and Saul 'Canelo' Alvarez (super middleweight).

Charlo and Castano's first clash in Texas last July ended in a split decision draw, with one judge scoring it 117-111 for Charlo, another 114-113 for Castano, and the other 114-114.

On Saturday, it looked as if both men were unwilling to risk leaving it to the judge's cards again in a fight that erupted from the opening bell.

Both boxers landed heavy shots in the first six rounds, with very little to choose between either man. But Castano appeared to tire noticeably in the seventh round, and Charlo's crisper punches began to take their toll.

"I listened to my corner this time," Charlo said. "I saw that he was wearing down a little bit and I was breaking him down. I just saw my punches being more effective."

Charlo repeatedly landed solid shots in the eighth and ninth, but Castano was never totally out of contention, still causing problems with his stinging right hand.

The end came quickly in the 10th, however, after Castano was knocked to the floor with a brutal Charlo combination. The Argentine did well to get back to his feet but was unable to respond when Charlo unleashed a final combination that sent him to the canvas once more.

"I was pretty sure he was going to get back up because it was only the first knockdown -- but I knew it was over," Charlo said afterward.

Castano, meanwhile, paid tribute to his victorious opponent.

"Everything that happened in the ring tonight, we showed that we are warriors," he said. "That's the main thing. We have to feed our families.

"We both were fighting back-and-forth. It was power back-and-forth and then his right hand came over and stopped the fight. He's a champion. He hit me. He got me. But I'm OK."