Mirko Filipović
Duffee was set to make his UFC debut against Mostapha al-Turk at UFC 99 until the UFC pulled Duffee from the fight. Duffee was replaced by Mirko Filipović. He was next announced by the UFC to face fellow UFC newcomer Mike Russow. However, Duffee was then pulled from that match and instead was matched up against Tim Hague at UFC 102. Duffee set the record for the fastest KO in UFC heavyweight history (0:07) after flooring Hague with a stiff jab and rendering him unconscious with follow-up ground and pound. After the finish, he celebrated to the camera by saying "That was an appetizer, I want to eat now Dana, let me eat!"