Re: Muhammad Ali's defensive skills
Early in his career, Ali had quick defensive reflexes, and fast footwork. Since he was the larger man in nearly every fight, he was extremely hard to catch, particularly in the opening rounds of the fight. In his second career, Ali lost the reflexes and foot speed that made him special, however he developed world class clinching skills.
Due to his unorthodox style, showboating and low guard, Ali was often open to hooks and jabs. Indeed, Frazier, Banks, and Cooper floored Ali with left hooks. Hitting Ali with jabs was accomplished at all phases of his career by Jones, Norton, Lyle, Young and Holmes.
I would say Ali had a good overall defense, but it’s also highly over rated.