#6. Junior Dos Santos
Junior Dos Santos is a former UFC Heavyweight Champion and is currently the number two ranked UFC Heavyweight contender.
The Brazilian Heavyweight slugger emerged onto the UFC scene in October of 2008 with a one-loss pro MMA record, knocking out Fabricio Werdum in his Octagon debut.
Dos Santos would go on to win his next eight fights, six of which came by way of KO or TKO, including a 64-second knockout of Cain Velasquez at the first ever UFC on FOX event to become the UFC Heavyweight Champion.
JDS would defend the title once, a second round TKO of former two-time champion Frank Mir at UFC 146 in May of 2012, before dropping it back to Velasquez after a five-round decision loss at UFC 155 in December of 2012.
“Cigano” rebounded with a spectacular spinning head kick knockout of Mark Hunt at UFC 160 in May of 2013 to earn himself a rubber match and another shot at the title against champion Cain Velasquez.
Unfortunately for Dos Santos, Velasquez would go 2-1 in the series, leaving JDS in a position where it’s going to be a while before he can lay claim to a fourth fight with Velasquez for a chance to regain the UFC title that once belonged to him. He is, however, without question, one of the top ten most dominant heavyweight champions in MMA history.