American Jermell Charlo defeated Argentinian Brian Castano by knockout to become the first holder in history of the unified super-welterweight belt on Saturday in Los Angeles.

Charlo, who conceded a controversial draw against the same opponent last year, won in the 10th round. The American was the holder of the WBC, WBA and IBF belts, and Castano of the WBO title.

In the outdoor arena at Dignity Health Sports Park, the 31-year-old American knocked his opponent to the mat twice in the 10th round as he began to gain the upper hand in a fierce fight that saw the two men share the first times.

A powerful right hook to the body rattled Castano and Charlo followed with a left hook to the head that sent the previously undefeated Argentine crashing to the ground.

Castano managed to get up, but unsteady on his feet, he couldn’t cope with the last two blows from Charlo which sent him to the ground for the last time.

“It’s amazing,” said the winner. “It was nerve-wracking. It was like a first fight, where you are nervous. I had ants in my legs”.

“I knew Castano was going to give it my all, and I trained very hard,” added the native of Richmond, Texas, whose record goes to 35 wins, one draw and one loss (19 KOs).

This triumph brings him into an exclusive club of fighters. He becomes indeed only the seventh boxer to hold at the same time the four belts of the main federations (WBC, WBA, IBF and WBO).

The six men who have done it before him are Bernard Hopkins (middleweight), Jermain Taylor (middleweight), Terence Crawford (welterweight), Oleksandr Usyk (light heavyweight), Josh Taylor (welterweight ) and Saul “Canelo” Alvarez (super middleweight).