As an Ecuador fan, glad to see Castillo getting his chance.
He's definitely rusty (as some have pointed out), but what's important to understand is the dimension he adds to the team. As I've mentioned before, he's not an exciting type of player, but he is a natural defensive mid, and his whole job is to free up the attacking players to do their job. Notice how much ground he covers, he patrols the midfield, you almost always see him on the TV screen.