Agreed that Iron Mike had a better mastery of the fundamentals than the Brockton Blockbuster but prime Tyson went into his fights to seek and destroy his opponents so that might not matter as much as some might think. Regardless of what some may say about Rocky's competition (which is by no means any fault of Marciano) he took on all comers and had tremendous power, chin, and heart. He had the chin to stay with Mike for several rounds and he had the power to catch Tyson with a KO punch. I think that this one could go either way.