(Updated at 12:45 a.m., June 28, 2021)

Filipino boxing great Sen. Manny Pacquiao's fight against World Boxing Council and International Boxing Federation welterweight champion Errol Spence Jr. may not push through.

The bout set on August 21 at the T-Mobile Arena in Las Vegas, Nevada could not happen, as Pacquiao faces a breach-of-contract lawsuit from Paradigm Sports, which seeks to reimburse a $3.3 million advance and an order to stop the Pacquiao-Spence fight, according to The Athletic's Lance Pugmire on Sunday (Philippine time).

Paradigm Sports head Audie Attar filed the lawsuit in Orange County, California, claiming Pacquiao made a breach of contract with Paradigm by not fighting four-division champ Mikey Garcia. The 42-year-old Pacquiao, who holds a 62-7-2 card with 39 knockouts, signed with the sports agency in February 2020.

The lawsuit stated Paradigm Sports was under the impression Pacquiao would sign the negotiated fight only to witness the only eight-division world champion announce he is fighting Spence Jr., instead, hours later in May.

Paradigm said it was never involved by any means in the Pacquiao-Spence fight even if it owns the exclusive rights to schedule Pacquiao's next two immediate fights. The development also led Garcia to cut his stint with the said sports agency short.

On Saturday, Pacquiao bared in Noli Eala's Power and Play program Garcia was indeed one of his final three choices as his next opponent. The other two were Spence and World Boxing Organization welterweight titlist Terrence Crawford.

According to the lawsuit, The Athletic further reported, Pacquiao and Paradigm were pushing for a four-fight deal with DAZN starting with a bout against Garcia in the first of a two-fight appearance in Saudi Arabia last year.

With others and Pacquiao's longtime advisor and president of his Manny Pacquiao Promotions Sean Gibbons undermining it, the lawsuit claimed, Attar went on to arrange a Pacquiao fight against Ultimate Fighting Championship star Conor McGregor, who is also under Paradigm.

With McGregor's loss to Dustin Poirier in January this year, however, the proposed fight didn't push through. This paved the way for Paradigm to push for a Pacquiao-Garcia fight anew, but the fighting senator of the Philippines ultimately decided to fight the 31-year-old Spence Jr., who sports an undefeated 27-0 record laced with 21 knockouts.

'Pacquiao's breaches of the agreement therefore entitle Paradigm to monetary damages (and) costs associated with this proceeding, including but not limited to attorneys' fees and injunctive relief,' wrote Paradigm attorney Judd Burstein in the lawsuit.

Part of Pacquiao's breaches of contract, the lawsuit stated, was he is ought not to fight again for Premier Boxing Champions unless the opponent was Floyd Mayweather Jr., who defeated him by unanimous decision in 2015.

Gibbons and friend Winchell Campos, the lawsuit claimed, swayed Pacquiao back to boxing manager Al Haymon's PBC and he signed to fight Spence in a pay-per-view bout.

Paradigm said Pacquiao did an immeasurable damage to its reputation.

'In addition to the millions of dollars in straightforward economic loss Paradigm stands to suffer, the damage to its reputation resulting from Pacquiao's breaches is incalculable,' wrote Burstein in the lawsuit.

'Just when Paradigm was at the cusp of establishing itself as a major player in professional boxing, Pacquiao left its reputation as a boxing representative in tatters.'

Pacquiao's camp, however, shrugged off the lawsuit, saying it's just a mere effort of Paradigm to stop the Pacquiao-Spence fight.

'The complaint filed by Paradigm Sports in California state court on June 25, 2021 is a frivolous effort to interfere with Manny Pacquiao's upcoming mega-fight, and it can and will fail for numerous reasons,' said Dale Kinsella, a lawyer representing Pacquiao in the United States.

'Moreover, had Manny Pacquiao known Paradigm Sports appears to have had no intention of fulfilling its contractual obligations, he never would have entered into any relationship with them. Should this matter actually proceed beyond Friday's filing in a court of law, Mr. Pacquiao will vigorously defend this action, assert his own claims against Paradigm Sports, and seek to recover his attorney's fees as well.'