John Riel Casimero was set for a huge bantamweight unification clash with Nonito Donaire before it all fell apart. Instead of a bout with Donaire, a fellow Filipino star, Casimero will step into the ring on Saturday to face former world champion Guillermo Rigondeaux (10 p.m. ET, Showtime).

Disputes over drug testing -- with Donaire's side suggesting Casimero balked at Voluntary Anti-Doping Association drug testing protocols, which Casimero denied -- led to Casimero insulting Donaire's wife. As the anger built, Donaire called off the bout entirely.

Casimero's consolation prize was a fight with Rigondeaux, which will take place at Dignity Health Sports Park in Carson, California. Losing out on the Donaire fight not only cost Casimero one of the biggest fights possible but landed him against one of the greatest tactical fighters of the modern era. Even at 40 years old, Rigondeaux is a threat to anyone with a crafty and deliberate approach, even if that has produced some less than thrilling outings in the ring.

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Casimero is riding a six-fight winning streak. While his level of opposition doesn't quite compare to who Rigondeaux has faced in his career, Casimero has proven that his style is capable of overwhelming tacticians. That was very much on display in his third-round TKO of Zolani Tete in November 2019, a win that secured Casimero a championship in the third weight class in his career.

"I respect Rigondeaux because he's a good boxer and a two-time Olympian," Casimero said at the pre-fight press conference. "But I want to show to the world that I can knock him out and a lot of my fans want to see me knock him out. So that's what I'm going to do. ... I have a surprise for Rigondeaux on Saturday night. He will maybe last three rounds. Don't run!"

"All these jokers always talk a lot about making me retire, but they have to do it in the ring. Let's see what you do on Saturday. I'm still right here. I'm enjoying this back and forth right now. It's heating up. He's going to have to back it up on Saturday night," Rigondeaux said through a translator at the final press conference.

"He's knocked out six guys in a row, but none of them are in the same class as me. He's going to have the devil in front of him on Saturday."

Casimero and Rigondeaux headline a tripleheader event on Showtime. The card opens with another pair of bantamweights looking to make a name for themselves when Rau'shee Warren takes on Damien Vasquez. Warren has won four of his last five bouts with the lone loss coming that the championship level against Nordine Oubaali. Plus, Gary Antonio Russell is back in the co-main event when he takes on Emmanuel Rodriguez for the interim WBA bantamweight title. Russell is undefeated so far in his career with 12 knockouts in 18 fights and is coming off a win over Juan Carlos Payano in December.

Below is the complete fight card with the latest odds from Caesars Sportsbook.

Casimero vs. Rigondeaux card, odds

FavoriteUnderdogWeight class

John Riel Casimero (c) -175

Guillermo Rigondeaux +150

WBO bantamweight title

Gary Antonio Russell -190

Emmanuel Rodriguez +160

WBA interim bantamweight title

Rau'shee Warren

Damien Vazquez



The seemingly uncrackable puzzle of Rigondeaux's style crumbled against Vasiliy Lomachenko in 2017, with Rigondeaux quitting on his stool after six rounds. Casimero will hope that his pressure and output can have similar effects -- and he does have two-handed power. The other thing Casimero possesses, however, are holes in his technique that can be exploited by a technician on Rigondeaux's level. There are really only two ways the fight can play out. Either Casimero's pressure is enough to drive him through the movement and pure boxing of Rigondeaux or Casimero continually runs into sharp counters while being outboxed by the Cuban. Pick: Guillermo Rigondeaux via UD