The 27 year-old, who is now unbeaten in 27 contests, engaged with the WBC title holder from the off and had Ponce De Leon down in the second round before stamping his authority in the third with the better quality of punches.
Ponce De Leon, 32, came back in bursts between Mares proving his superior skills, and just as the fight seemed to swinging away from the challenger, a big right hand in the ninth was the beginning of the end.
A stunned Ponce De Leon went down hard and as Jay Nady counted to eight, the champion was still on unsteady legs as Mares sensed the end was nigh, continuing his onslaught against the ropes.
Nady had seen enough as Ponce De Leon’s head was rocked back on three more occasions and Mares was declared the winner to once again pick up a WBC belt, along with a boost up the pound for pound rankings.
Some huge match-ups await the new featherweight king in the future, with Mares undoubtedly the biggest draw in the division on the back of his impressive victory over a seasoned campaigner in Ponce De Leon.