Clement Lenglet called for patience around Ansu Fati after the teenager's excellent display in Barcelona's 5-2 win over Valencia.
The 16-year-old marked his first Barca start with a goal and an assist inside seven minutes at Camp Nou on Saturday, adding to his maiden strike against Osasuna before the international break.
It made Fati the youngest player to score and assist in a single LaLiga game in the 21st century.
He was replaced by Luis Suarez in the 60th minute and the Uruguay international scored twice, with Frenkie de Jong and Gerard Pique also on target for Ernesto Valverde's side.
Asked about Fati after the match, defender Lenglet told Movistar: "He is 16 years old and we have to be calm with him. It's true that he has taken advantage of his minutes and is a good boy who deserves it.
"I am very happy for him, but we have to give him time because he is 16 years old and things can change quickly. I hope they don't but we have to take care of him.
"[I would advise him to] listen to people and work hard because playing for Barca is very difficult."
Kevin Gameiro was granted a goal after a lengthy VAR review of an offside decision before half-time, while Maxi Gomez opened his Valencia account in the second minute of stoppage time at the end of the game.
"It was a good victory against a difficult opponent who plays good football. They play different football to us but we did things very well," said Lenglet.
"We prefer not to concede goals, but we did things well until the end. On the whole we played a good game and although we conceded the response was important."