Johnson beats DM up and stops him late. DM does horribly against the golden era guys of the 70s/80s. He loses badly against Spinks, Saad, Qawi, Eddie MM, Galindez, Conteh, Johnson, Lopez, ect. Not only them, but I'd pick Rossman at his best over DM. DM would fare better against the late 80s guys like Harding, Andries, Charles Williams, Lalonde. I think he beats those 5 guys.
