Rios does hit hard - no doubt, and especially in close. If he can get into that range where he's at his most deadly, he'll be able to do harm. He's no one-punch-killer, but really - neither is JMM.
Pac-Man may very well take Rios out. I believe he does. And his ability to take punishment may still be good - but not as good as before. The neurological ability to withstand violence to the brain differs vastly between individuals. But the day comes when even the most resilient, hardheaded m-f is affected if he doesn't get out of the game in time.---Grimm also wonders when the jig will be up for Pacman