If anyone knows former UFC heavyweight champion Cain Velasquez, it's fellow former champ Junior dos Santos.
The pair have a bit of a history. In 2011, Dos Santos shocked the world when he KO'd Velasquez in 60 seconds to claim the heavyweight title during the UFC's debut event on FOX.
Velasquez reclaimed the title in 2012 at UFC 155, scoring a unanimous decision. In the 2013 rubber match at UFC 166, Velasquez battered Dos Santos in brutal fashion before scoring a TKO late in round five.
So imagine Dos Santos' surprise at seeing Fabricio Werdum, a man he knocked out in his promotional debut at UFC 90, pick Velasquez apart before submitting him at UFC 188 in June.