Jake Paul fired back at Canelo Alvarez on Friday night, claiming that the four-division champion "ducked" a fight with him to sign a lucrative deal with Riyadh Season.

In a video posted to social media, Paul showed what he said was a contract signed by himself and Alvarez for a fight that the two sides were set to formally announce next week. Sources told ESPN's Mike Coppinger on Thursday that Alvarez and Paul were finalizing a deal to fight May 3 in Las Vegas.

But in a stunning development, Alvarez changed course hours later Thursday and instead completed a four-fight deal with Turki Alalshikh and Riyadh Season, effectively killing the fight with Paul that was expected to land on Netflix.

"The truth is, you could be bought," Paul, addressing Alvarez, said in his video. "You're a money-hungry squirrel chasing your next nut. The truth is, these sports-washing, shady characters are paying you hundreds of millions of dollars to stop our fight from happening because they couldn't fathom the fact that they can't create a bigger fight than me and you."

Sources told ESPN that Alalshikh, the chairman of Saudi Arabia's General Entertainment Authority, told Alvarez that the deal with Riyadh Season -- which included a Sept. 13 megafight with former undisputed welterweight champion Terence Crawford in Las Vegas -- would be off the table if he proceeded with the planned fight with Paul.

After Alvarez's deal with Riyadh Season was announced, Alalshikh told ESPN, "Canelo only fights real fighters," a not-so-subtle shot at Paul and the deal with Alvarez that fell through.

"Claiming he's not fighting YouTubers. Bulls---," Paul said in his video. "Claiming he's fighting real fighters, but he's fighting Crawford, a 135-pound fighter, and running from a real fighter like David Benavidez."

Crawford, ESPN's No. 2 pound-for-pound fighter, began his career as a lightweight but recently made his 154-pound debut with a victory over Israil Madrimov in August.

Paul took one final shot in his video, challenging the notion that Alvarez is boxing's top star.

"You call me a YouTuber, but you've never had a boxing match as big as mine," Paul said. "I promise you one thing, Canelo. Any fight that you do this year, mine will be bigger."

Paul, 28, gained fame as a social media star who turned into a boxer and has an 11-1 record. He is one of boxing's top attractions despite his novice skill level. His November fight with the 58-year-old Mike Tyson, which Paul won via an eight-round decision, peaked at a staggering 64 million concurrent streams on Netflix.

Alvarez, 34, is the unified champion at 168 pounds and is a former 175-pound champion. He has surpassed 1 million pay-per-view buys several times, including twice during his legendary trilogy with Gennadiy Golovkin.