No. 1: Matt Serra-Georges St. Pierre (UFC 69)
Photograph By Josh Hedges/Getty Images
Matt Serra became the longest long shot in history when he earned a shot at the UFC's welterweight title by winning Season 4 of "The Ultimate Fighter" in autumn 2006. His subsequent fight against St. Pierre seemed nothing more than a cute little reality-show gimmick, until the 6-to-1 underdog stumbled the champion with a winging overhand right a little more than three minutes into the first. He followed that punch with another, then another and (as St. Pierre tried unsuccessfully to collect himself) capped MMA's greatest upset by knocking GSP senseless with a flurry on the ground.