It marked the young striker's first senior goal for Atletico.
"He's working well, he's training well. it's important for his growth. As long as there is humility, the heart always responds," Simeone told Movistar.
"We are happy, we needed a match that would give us a good feeling. We were able to take the game where we wanted and we were able to win a necessary and important match.
"He did what he had to do, that's why he is at Atletico. He has a responsibility that has no name, they are footballers... those who run play and those who run less, play less.
"The club didn't spend money to buy a son, he is a boy who was in the youth academy, we believe he can help. He will have good games and bad games, but for sure he has what it takes."
Atletico captain Koke admits he is happy Giuliano Simeone, who has recovered from a broken leg suffered last year.
"I've known him since he was very young and I'm happy to see his progress, especially after his serious injury last season," Koke said. "He's showing that he has the level to be with us and compete and score goals."