The Dutchman was taking charge of his first game with the Rossoneri and a late penalty from Mario Balotelli ensured that he started his reign with three points at the San Siro.
"We formed a circle all together in the locker room and I said we'd do the same after every game, whether it's a win or a defeat, so we can all look each other in the eye. We're all responsible for every result," he told Sky Sport Italia.
"The victory is certainly dedicated to all the Milan fans. I am happy for the squad, as there is a lot of work to do and a win makes it all feel easier. I am concentrated on what we want to develop next week, which will be the first real week to get training done and concentrate on all the aspects of building the football I've got in mind.
"Right now we want to focus on rediscovering the joy of playing football and training with the ball, so the players can connect with the ball. This victory came at the end with a penalty, but I still believe it was deserved considering the performance over 90 minutes."
Milan are currently 11th in the Serie A table.