This Saturday night, Conor McGregor has promised to knock out Chad Mendes. Only one fighter has already done that in Mendes's career, Jose Aldo Jr.

McGregor's original opponent for this Saturday's fight has already fought Mendes on two occasions. They fought last year in a Fight of the Year contender which Aldo won by unanimous decision. They also fought in 2012 in Brazil. 

That fight was the American's first loss as a professional as Aldo won the fight with just one second left in the opening round. The Brazilian shocked Mendes with a knee to the head before the referee halted the fight.

Aldo's knockout victory resulted in the UFC's most iconic post fight celebration as the Champion ran into the crowd to celebrate with the Rio de Janeiro faithful.