Chris Arreola underestimated Andy Ruiz Jr. the first time they sparred.

Ruiz was a 16-year-old amateur the day he walked into Lincoln Boxing Club in Riverside, California, eager to test himself against the Mexican-American heavyweight contender he admired. Arreola took one look at Ruiz and asked his former trainer, Henry Ramirez, if he was serious.

“I remember telling Henry, I was like, ‘Really, I’m gonna spar with this kid?’ ” Arreola told “Because he had a baby face, and he was a chubby kid. But once the bell rang, this kid was throwing bombs and throwing some fast hands.”

Arreola realized at that moment he would face Ruiz in an official fight one day.

“I’m telling you, man, that kid surprised the sh*t out of me,” Arreola said. “And I knew that he was someone that I was gonna have to deal with sometime in the future. And here we are.”

Ruiz (33-2, 22 KOs), of Imperial, California, and Arreola (38-6-1, 33 KOs, 2 NC), a Riverside native, will finally fight Saturday night. Their 12-round bout will headline a four-fight FOX Sports Pay-Per-View show at Dignity Health Sports Park in Carson, California (9 p.m. ET; $49.99).

Both boxers have reflected on that initial sparring session during the buildup toward their fight.

“We slugged it out,” Ruiz told “I was 16 years old. Everybody was impressed with the hand speed and the way that I popped. … There was a few times that we sparred. I learned a lot from him when I was in there, but I felt like I could do so much better. I was still a young, little kid with a dream.”

Arreola admits they’ve experienced a role reversal since they sparred when Ruiz was just an ambitious teenager. While Arreola lost each of his three heavyweight title fights, Ruiz became the first fighter of Mexican descent to win a heavyweight championship when he upset British icon Anthony Joshua by seventh-round technical knockout in June 2019 at Madison Square Garden in New York.

The 40-year-old Arreola now looks up to the 31-year-old Ruiz for what he accomplished against Joshua.

“I wanted to be like him because he was a Mexican contender,” Ruiz recalled. “I wanted to be in his position as well. We had the same dream. We wanted to become the first Mexican heavyweight champion of the world. And to tell you the truth, I thought he was gonna do it because he was way ahead of me. And at that time, I was just trying to qualify for the Olympics for Mexico. But you know what? Things turned out different. Praise to God that I ended up becoming the first Mexican heavyweight champion of the world.”

Ruiz recognizes the invaluable lessons he took from sparring against Arreola in those formative years. The former IBF/IBO/WBA/WBO champ remains appreciative of Arreola providing him with much-needed experience and considers his upcoming opponent a friend.

“I have nothing bad to say about Chris,” Ruiz said. “He’s a good friend. He’s a good human being. But inside the ring, it’s all business. We’re all trying to feed our loved ones and, you know, the best man wins on May 1st.”

Keith Idec is a senior writer/columnist for He can be reached on Twitter @Idecboxing.