Jack Swagger and CM Punk are former WWE World Heavyweight Champions turned MMA fighters ... but that's where the similarities end, 'cause Swagger tells TMZ Sports when he fights, he ain't losing.
Big facts ... Swagger -- real name Jake Hager -- was a pro wrestling superstar. But, he was also a stud on the wrestling mats in college -- earning All-American honors at Oklahoma in '06.
That's precisely why 6'7", 265 lb Swagger says when he steps into the cage to fight J.