Referee Mark Clattenburg (C) shows a red card to Arsenal's German defender Per Mertesacker (2nd R) after his challenge on Diego Costa (not pictured) during the English Premier League football match between Arsenal and Chelsea at the Emirates Stadium in London on January 24, 2016. AFP PHOTO / IKIMAGES RESTRICTED TO EDITORIAL USE. No use with unauthorized audio, video, data, fixture lists, club/league logos or 'live' services. Online in-match use limited to 75 images, no video emulation. No use in betting, games or single club/league/player publications. / AFP / IKIMAGES (Photo credit should read IKIMAGES/AFP via Getty Images)
