Iran Barkley against Tommy Hearns.

How about Tommy Hearns choosing to outbox rather than outbang Wilfredo Benitez? Who the hell could have seen that coming?

Max Schmeling standing in the pocket and counterpunching Joe Louis?

Muhammad Ali's rope a dope against George Foreman?

I think the question itself is a hard one though. 99% of all fighters, even really good ones, can only fight one way and be successful. They can emphasize a certain punch etc on a given night but they can't really utilize a different approach than the one that got them there.