CARSON, Calif. (AP)Jermell Charlo and Brian Castano both fell agonizingly short of becoming the first undisputed super welterweight world champion when they fought to a split draw 10 months ago.

That disappointment only fueled both fighters’ desire to get it right in their highly anticipated rematch.

Charlo (34-1-1, 18 KOs) takes on Argentina’s Castano (17-0-2, 12 KOs) for all four major 154-pound belts Saturday night in the famed outdoor tennis stadium in Carson, south of downtown Los Angeles.

Only six fighters have ever held every major title in their respective weight classes during the four-belt era, but the chance at history only makes this rematch slightly more enticing to both fighters.

The action-packed first fight itself would be enticement enough: The vaunted Charlo was a 3-1 favorite with superior size and reach, but he had to scrap just to eke out a draw when Castano put on a superb display of resourcefulness and tenacity.

”I’m going to use everything I learned from that (first) fight on Saturday night,” Charlo said. ”I’m going to take advantage of the things that I have that he doesn’t have. I’m going to use the skills I’m blessed with. I’m going to be stronger, faster and smarter than I’ve ever been before. Thank you, Castano, for giving me more time to prepare myself.”

Charlo holds the WBA, WBC and IBF super welterweight titles, while Castano is the WBO champion.

Castano thought he did enough to win in his gutsy performance in the first bout. The three ringside judges in Charlo’s native Texas couldn’t decide, however: One judge gave it widely to Charlo and another gave it narrowly to Castano – and the third scored it a draw.

”The first fight motivated me because I thought that I won,” Castano said through a translator. ”I learned that I can’t leave this fight in the hands of the judges. I need to leave no doubt that I’m the superior fighter.”

Castano is significantly smaller and less experienced, and also slightly older and slower than Charlo. Those disadvantages paled in comparison to the size of his heart in the first bout. Castano also figured out how to get inside Charlo’s jab, presenting problems that Charlo struggled to solve all night.

Both fighters were hurt at times in the back-and-forth bout. Castano pushed forward relentlessly while Charlo attempted to win through counterpunching off the ropes, unable to unleash his impressive power or to generate his usual volume of effective offense.

But Charlo has shown plenty of heart during his career as well: His only loss was a shocking knockout from Tony Harrison in 2018, but he avenged it and reclaimed his WBC belt a year later.

This rematch was initially scheduled for March, but Castano tore his biceps muscle and had to train essentially with one arm for several weeks. Both fighters say they’re healthy and excuse-free for this visit to the outdoor arena where crazy things have happened regularly in fights over the past two decades.

Unbeaten welterweights Jaron Ennis and Custio Clayton meet in the most anticipated undercard bout.

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