Joseph ‘JoJo’ Diaz and William Zepeda have been respectful throughout fight week, even as each has vowed to kick the other’s ass on Saturday.

Their friendly rivalry extended through the obligatory staredown following Friday’s weigh-in, with Diaz immediately stepping to Zepeda who sported a grin during their brief encounter. Both came within the contracted weight limit of 138 pounds for their scheduled twelve-round bout, which takes place Saturday evening on DAZN from Pechanga Arena in San Diego, California.

Diaz (32-2-1, 15KOs)—a 2012 U.S. Olympian and former IBF junior lightweight titlist from South El Monte, California—was 137.5 pounds for his third straight fight at lightweight since officially moving up last summer. Zepeda (26-0, 23KOs) came in at a chiseled 137 pounds for his first U.S. televised main event, having developed a cult following as an entertaining figure on Golden Boy undercards.

Diaz has not fought since a competitive but clear points loss to Devin Haney in their WBC lightweight title fight last December 4 in Las Vegas. Haney has since fully unified the division following a pair of decision wins over George Kambosos, Jr., while Diaz hopes to position himself for a second lightweight title shot in 2023.

Diaz previously held the IBF junior lightweight title, which he lost at the scales ahead of a 12-round draw with Shavkat Rakhimov last February 13 in Indio, California. The development prompted a move up to lightweight where he outpointed Javier Fortuna last summer before the aforementioned defeat to Haney.

Zepeda previously enjoyed a fifteen-fight knockout streak before going the distance in his most recent outing. The 25-year-old southpaw from San Mateo Atenco, Mexico outpointed former secondary WBA junior lightweight titlist Rene Alvarado over ten rounds on May 14 in Ontario, California.  

In the evening’s lone major title fight, Leonela Yudica defends IBF flyweight title against former three-time titlist Arely Mucino.

Argentina’s Yudica (18-0-3, 1KO) was 114.4 pounds for her tenth defense of the IBF title she has held since December 2014. Monterrey, Mexico’s Mucino (31-3-2, 11KOs) was pounds as she bids to win her fourth major title, all at flyweight. Mucino is the wife of former WBO junior flyweight titlist and current flyweight contender Angel ‘Tito’ Acosta.

DAZN Undercard, 8:00 p.m. ET/5:00 p.m. PT.

Alexis Rocha (20-1, 13KOs), Irvine, California, 146.4 pounds vs. Jesus ‘Ricky’ Perez (24-3, 18KOs), Tijuana,146.7 pounds—10 rounds, welterweight

Hector Valdez (15-0, 8KOs), Dallas, Texas, 121.4 pounds vs. Max Ornelas (15-0-1, 5KOs), Las Vegas, 120.6 pounds—junior featherweight      

Preliminary undercard, Golden Boy YouTube, 4:30 p.m. ET/1:30 p.m. PT.

Jorge Chavez (3-0, 3KOs), San Diego, 127.2 pounds vs. Adrian Leyva (3-3-2, KOs), Houston, Texas via Guantanamo, Cuba, 127.4 pounds—6 rounds, featherweight        

Japhethlee Llamido (9-0, 3KOs), Norwalk, Connecticut 126.2 pounds vs. Pablo Cruz (22-5-1, 6KOs), Houston, Texas, 128 pounds—8 rounds, featherweight

Asa Stevens (2-0, KOs), Walanae, Hawaii,122.6  pounds vs. Mychaquell Shields (pro debut), El Cajon, California, 122.8 pounds—4 rounds, junior featherweight               

Jan Salvatierra (8-2, KOs), Los Cabos, Mexico, 111.4 pounds vs. Robert Ledesma (3-8, KOs), San Antonio, Texas, 111.4 pounds—4 rounds, flyweight

Jake Donovan is a senior writer for BoxingScene.com. Twitter: @JakeNDaBox