So much for the new Invincibles. Arsenal were brought back down to earth with a shuddering bump by a scintillating display from Brighton as Fabian Hürzeler’s vibrant side celebrated the club’s 125th anniversary in style. The special edition shirts they wore to mark the occasion will end up being collector’s items after the Premier League champions were ripped apart. Arsenal were attempting to record an eighth successive victory in all competitions to start the new campaign for the first time si…