In this ambitious spot for Porsche's new 911, Muhammad Ali, Maria Sharapova and world chess grandmaster Magnus Carlsen face off against arguably their most formidable opponents: themselves.

The new ad out of Cramer-Krasselt uses dazzling special effects to pit the iconic champs against their doppelgangers to illustrate the idea that the only car worthy enough of competing with a 911 is the 911 itself. "Greatness comes from within, from pitting you against you," a voiceover recites.

The ad was directed by Mark Jenkinson of Persuade & Influence, while Darrell Foster, the trainer who primed Will Smith for his role as Ali, worked with the actors playing Ali. The effects pros at the Mill then superimposed Ali's face on their bodies with meticulous CG work.