Extreme Fighting was the first promotion in the US that introudced weight classes. Operating between 1995 and 1997 for only 4 events both the UFC HW and LHW would fight the former EF champions in their first title defenses. While LHW champ Igor Zinoviev was KO'd within seconds by Frank Shamrock and never fought again HW champion Maurice Smith won the UFC belt over Mark Coleman. 2 of Frank Shamrocks other title opponents had prior fights in EF, John Lober who fought Zinoviev to a draw and Kevin Jackson who finished Lober. Another notable is Mario Sperry who after losing to Zinoviev for the inagural EF LHW title in 1995 never lost again until Pride 20 where he was stopped by Murilo Rua.