Claressa Shields says a knockout isn't enough for her 2nd MMA fight ... she's trying to BREAK BONES, telling TMZ Sports she's been putting in a ridiculous amount of work in the gym, and is ready to go!
26-year-old Shields -- regarded by many as the greatest female boxer in the world -- is set to return to the cage for her 2nd MMA fight on October 27 at a big PFL event in Hollywood, FL ... taking on 21-year-old Abigail Montes.
"She a decorated amateur kickboxer. Even though she only has 2 fights in MMA, she's been kickboxing for I don't know how many years in Mexico," Claressa says.