Honestly I think bruce would hold up well in this fight. Ali has fought and trained for bouts based on rules. Bruce did not. Hell, he said himself, in a real fight, he would go for nut punches, eye gouges, biting, etc. And with quick strikes like these, Bruce would be at an advantage speed wise. He was as fast as light weight boxers and defeated the amateur British champ in his youth. Obviously this is a far cry from Ali, but at least he is familiar with boxing. How familiar is Ali with a well rounded MA? In a ring bout with rules, Ali wins everytime, (size and strength would be near impossible to overcome) but just out of the blue,no holds barred, I think Bruce takes the majority slightly.