BTW,the defence was exposed in the counter-attack that led to the penalty becouse of him,even more than DC.
If u see it from the beginning,u will find that melo noticed the presence of the player on the right side n instead of covering him he blindly went to the player with the ball who was already facing Giorgio.
Now some of would say that their right winger is DC's one,that is true but in that case DC had to cover the player who was behind Giorgio n he did indeed.
If Melo has covered that right winger,the player with ball would had not played it to him n instead he would have chosen to dribble Giorgio,the thing that he will never be able to do even in his dreams.