Who was the first person to knockdown Mike Tyson?

As a Pro, James Buster Douglas

allthough buster douglas knocked mike tyson down and eventually beat him he wasnt the first to knock him down,the first person as a pro to knock him down was tony tnt tucker in a world title bout but the ref said it was a slip but was quite clearly seen as a punch to the head that did it als o james smith did the same but was looked at as a slip