MMA's Kayla Harrison Destroys Gervonta Davis for Roughing Up Women

MMA champ Kayla Harrison -- one of the baddest fighters on the planet -- is going scorched-earth on Gervonta Davis after the boxer got physical with his baby mama.

As we previously reported, 25-year-old Davis -- the reigning WBA lightweight champ -- got into a heated altercation Saturday night with his ex-GF at a celebrity basketball game in Miami.

Davis claims he "never once hit her" but admits he "was aggressive." The video appears to show Davis using his strength to rip the woman out of her chair in a fit of anger.

Enter, Harrison ...  a 2-time Olympic gold medalist in Judo and the reigning PFL lightweight champion who tells TMZ Sports she was DISGUSTED by Gervonta's actions.

"Completely inappropriate and wild," Harrison told us at the Sports Illustrated party in Miami..

"I'm in a violent field of business and that's never unacceptable ... ever, ever, EVER."

Kayla continued ... "There's a line that we as women have very clearly established that we're not taking any sh*t anymore."

As for Gervonta's actions ... Kayla says, "That's not okay. It's never gonna be okay again. And, I hope that he has repercussions for his actions."

Kayla also has advice for anyone in a situation where they feel their safety is at risk ... and it involves ferocious kicks to the nuts.