Canelo Alvarez Rips 'F***ing Asshole," "P****" Oscar De La Hoya

Canelo Alvarez is fighting on Saturday, but perhaps an opponent change is in order ... 'cause Saul went scorched earth on Oscar De La Hoya, as the legendary fighter sat just feet away.

"He's a f***ing asshole. That's what I say. He's a f***ing asshole. He tries to get attention for him, not Munguia. He's a f***ing asshole. He steals [from his] fighters. F***ing p***y. Motherf****r," 33-year-old Alvarez said, lashing out at the Las Vegas press conference just days before his fight with Jaime Munguia.

What pissed Canelo off? Well, the two boxing legends previously worked together for years as promoter and fighter ... but things ended poorly, and there's obviously no love lost.

Prior to Alvarez's outburst, ODLH said ... "There were times my work wasn't my priority based on my mental health which I neglected for so long but that doesn't change the fact that Golden Boy built Canelo Alvarez, period."

Oscar continued ... "The company you fought under for decades has always had one name and it's mine so put some f***ing respect on it."

Of course, that company is Golden Boy Promotions ... named after the Hall of Famer.

As for Saturday's fight, it's a compelling one. Munguia is young (27 years old), and has an undefeated 43-0 record with 34 knockouts.