Diaz, on-loan from Real Madrid, came off the bench to score late on.
“I am very happy to be here, as I feel really good at such a big club as Milan," Brahim Diaz told Sky Sport Italia.
“I play wherever the coach wants me to. I know that I have to improve and I'm very happy to be doing it at this club."
“Pioli's return was very positive. His staff allowed us to work well too, but his presence gives us an extra boost.
“We are satisfied with the performance."