One that I have never been able to find a tape of, but would have to be up for consideration was lightweight champ Jimmy Carter's defense against Tommy Collins (who was really a featherweight) ... over the span of just over 3 rounds, Collins was down TEN TIMES... It was a nationally televised fight and it caused a large uproar that ultimately led to the creation of the 3-knockdown rule... at one point, a noted politician (I can not recall who) rushed the ring apron and screamed at the referee "do you want MURDER?"
Sorry, I was unable to follow what happened there. Its not in English. Seems like a guy having the shit beat out of him unnecessarily, but with commentary like that, who knows.