Manny Pacquiao Promotions President Sean Gibbons, who promotes WBO bantamweight world champion John Riel Casimero, believes his fighter is taking on a tougher task when he faces two-time Olympic gold medal winner Guillermo Rigondeaux.

The two boxers will collide on August 14 in a Showtime televised main event from the Dignity Health Sports Park in Carson, California.

Casimero was originally scheduled to face Rigondeaux on the August date - but the contest was later shelved in favor of an all-Filipino unification between Casimero and WBC world champion Nonito Donaire.

However, there was an unexpected falling out between Casimero and Donaire - as the boxers and their respective team members were trading plenty of words on social media.

Eventually, Donaire announced his withdrawal after several insults were directed at his wife, who also doubles as the boxer's business manager.

“We jump on the sword and say there were some things that shouldn’t have been said. That’s boxing. We’re not in ballet, we’re in boxing," Gibbons told ESPN.

Once Donaire was officially out - the Cuban veteran was back in the fight.

Rigondeaux, although older at 40, has one defeat on his record - which took place in 2017 when he made a dangerous decision to move up by two full weight divisions to challenge Vasiliy Lomachenko at 130-pounds.

Among his notable wins, the Cuban stylist outboxed Donaire over twelve rounds in 2013 - when they collided in a super bantamweight unification.

Gibbons views the style of Rigondeaux as being the more difficult to overcome when compared to Donaire.

“I think we’re fighting the tougher fight, we’re fighting the guy who beat Donaire,” Gibbons said. “He’s only had one bad fight in his life and that was fighting a guy two divisions bigger than him, Vasiliy Lomachenko. Guillermo Rigondeaux … dude has a lot of life left in him. We’re taking on a very difficult challenge."