Pacquiao vs. Mayweather -- Promoter Sues Manager for $100 Mil ... He's 'Rigging Boxing'

Manny Pacquiao's manager Bob Arum is declaring war on Floyd Mayweather's promoter -- claiming the guy is "rigging the boxing industry" ... and taking aim at everyone, including Jay Z ... this according to a lawsuit obtained by TMZ Sports.

Arum's Top Rank boxing promotions company just filed a $100 MILLION lawsuit against Al Haymon -- who many consider the most powerful man in boxing.

According to the suit, Top Rank claims Haymon has been using unsavory tactics to monopolize the boxing industry -- including illegally blocking fights, blocking venues and freezing out other promoters, including Top Rank and Jay Z's Roc Nation Sports company.

Top Rank claims Haymon -- who "famously runs his empire from an old school flip phone" -- is leveraging his impressive client list (which includes Mayweather, Adrian Broner, Danny Garcia and more) to monopolize the boxing industry.

For example, Top Rank claims Haymon cajoled one of his fighters -- Peter Quillin -- to turn down a $1.4 million payday in 2014 (the biggest payday of his career) because Jay Z had won the right to promote the fight and Haymon didn't want to let Roc Nation get his foot into the boxing game.

Top Rank is going after Haymon and his financial backers, the Waddell & Reed investment group for fraud and conspiracy.