Mel handed Pedri a senior debut with Las Palmas before overseeing his sale to Barca a year ago.
He recalled, "In a preseason game at Benito Villamarín he faced Joaquín, who could have been his father. But he dribbles, scores himself, creates ... He has a long journey.
"We were with the president of Las Palmas in Marbella in the preseason, we saw Pedri and I said 'look at him, there goes the millionaire, but he still doesn't know'.
"When we saw him in the youth team, everyone thought the same: 'If he can do that with the professionals, he's a crack'."
Mel added: "We used to say to Pedri 'if you want to be top, you have to step in the area and look at the goal'. He knows that is what he has to improve."