If you’ve ever wondered what would happen if Muhammad Ali fought Muhammad Ali, this film gives us a hint. Three champions from different worlds -- boxing, chess and sports cars -- each considered “the greatest,” face off against themselves to illustrate the point that greatness is really something that must first be proven to yourself before you can prove it to others. In each case there’s a fierce battle. (In the case of Muhammad Ali, there’s also a striking example of the state of art in CGI.) At the end each competition has a winner. Of sorts. Because that’s the thing about champions, they don’t like losing. Even to themselves. And so we can assume that no matter how great this Porsche 911 is, another greater version is always sure to emerge.