Benn, 29, had earlier said Garcia is “like a big child, a spoiled brat”.
“He throws his toys out of the pram on social media, throwing little tantrums,” he added.
“I’m not too concerned about this little influencer. He ain’t a fighter. He can say whatever he wants, it ain’t going to make a difference come 12 September.”
Benn then pointed to himself and said: “12-round war proven. I don’t quit, I don’t stay down on one knee,” referring to Garcia’s loss to Gervonta Davis in 2023.
Garcia, 27, responded by saying Benn’s “not gonna make it to 12, he’s not good enough”.
“You think I’m going to let a guy from the UK come here and beat me and take my belt? You’ve lost your mind,” Garcia added.
Born and raised in California, Garcia has Mexican heritage and often carries both an American and Mexican flag into the ring.
“Wait till I smack you up and make you quit,” Benn added. “You have no heart. You’re not Mexican, bro.”
Benn, who spent 12 years of his childhood in Mallorca, Spain, then shouted at Garcia in Spanish while grabbing his crotch.
Garcia later said he would stop Benn inside five rounds before the stage was cleared for a face-off between the fighters.
Benn’s father, former world champion Nigel Benn, was standing behind him as he repeatedly shouted “you quit” and told Garcia “you ain’t got no heart. I’ll test it, I’ll test that chin too”.
Garcia replied by saying: “This about to be easy work. You not good enough to beat me. Your dad’s gonna stop the fight. I promise you.”