Well, if that word is "No" then yes, he can hold his own with Keyes.
All he has to do is say "I'm not debating."
Since Obama has a lock on the race, he will seek out debates with Keyes one, two, three, many times. He will seek it to make him a national figure, sort of like the Lincoln Douglas debates. He has nothing to lose, and much to gain. As I said, my money is that Keyes does not run.