Garnacho was a junior player inside Getafe's youth system before moving across town to Atletico Madrid ahead of joining Manchester United as a 16 year-old.
Mellado told The Sun: “I remember many times arguing with Alejandro in the middle of a game.
“He saw things his way and told them to my face without any beating around the bush. Other guys don’t even dare to ask why the coach makes his decisions.
“It’s not normal for a ten-year-old boy to tell you so many things about how he saw them. And he’d tell you straight, without any anaesthetic. I told him he was a right winger, and he said no, he was a left winger.
“Probably by now he doesn’t even remember these conversations I had with him. I used to tell him, ‘You’re right-footed, and you play on the right’.
“To motivate him, I’d tell him, ‘If you score two goals in the first half, you’ll play on the left wing’.
“I told him that once during a match. And he didn’t score two goals — he scored FOUR.
“Between you and me, I’ll tell you a secret: Alejandro ended up playing on the left wing.
“He scored more goals playing on the left side. He had a striking power with his right foot like a sledgehammer.”