I think "Fatty" hit Kapp with his cane, which takes a little luster off the one punch KO.
Anyway, the guy who got knocked down is Angelo "King Kong" Mosca. I had no idea he had a long career in the CFL, but remembered him as a villain from the old Mid-Atlantic/NWA territory. After seeing this yesterday, I read up on him a bit. If his wiki page is accurate, Mosca was from the same town as my dad (Waltham, MA) and just a few years older. He played his college ball at ND, went to the CFL and then wrestling.
I wonder what the organizers were thinking putting the two of them on stage together. Someone had to know that Kapp hates Mosca and that Mosca didn't think too highly of him.