I gotta agree with no pain = "super" strength in real life. Look at guys whacked out on drugs who end up needed 4 or 5 cops just to bring them down. When you're natural safeguards are gone, the human body can do amazing things. Sure, being painless doesn't make you any less susceptible to physical damage, but match up being painless with someone who is an expert fighter, has high intelligence (knowing what NOT to do to get too injured), and I'd say you've got a pretty formidable foe. Combine that with the fact that he's fighting a guy who doesn't kill (unless the most dire situation).