The game had been back-and-forth for a while until 19-year-old Argentinian stepped on to the field.
Nico Paz, who replaced Brahim Diaz in the 65th minute, unleashed a long-range strike which dipped before reaching the goalkeeper, ultimately causing a mistake from the Napoli goalkeeper Alex Meret.
In just his second Champions League appearance the talented Real Madrid Castilla player grabbed his first goal, with a little helping hand from the Italian team’s keeper.