Sin Piedad (2011) (Spanish for "No Mercy") was an annual professional wrestling major event produced by Consejo Mundial de Lucha Libre (CMLL), which took place on December 16, 2011 in Arena México, Mexico City, Mexico and replaced CMLL's regular Friday night show Super Viernes ("Super Friday"). The 2011 Sin Piedad was the tenth event under that name that CMLL promoted as their last major show of the year, always held in December. The main event of the show centered around a long running storyline between Blue Panther and the Casas wrestling family, represented by El Felino in this instance. The two wrestled in a Lucha de Apuesta hair vs. hair match where the loser of the match would be forced to have all his hair shaved off. The show featured four Best two-out-of-three falls Six-man tag te