Conversation so far:
What is the undisputed champion?
Expectations for Tyson were extremely high, and he embarked on an ambitious campaign to fight all of the top heavyweights in the world.
Tyson defended his title.
What year did he start that journey?
Tyson defended his title against James Smith on March 7, 1987, in Las Vegas, Nevada.
He won by unanimous decision.

Question: Who did he fight after this?
Self-contained rewrite: Who did Mike Tyson fight after James Smith?