De Jong scored the only goal of the game halfway through the second half when he headed home a Mario Balotelli free kick and the Netherlands international was quick to stress that his compatriot has been vital to the Rossoneri's resurgence in recent weeks.
"This victory is for Seedorf. People talked too much about his position this week, but he is very important for the squad," De Jong told Sky Sport Italia.
"This game was doubly important. Everyone saw in recent weeks how tough it was for our team, so it was fantastic to win and we must continue along this path for Europe.
"We have never given up, so we have to carry on and I believe we can get a place in the Europa League."
After a fifth win in six games, Milan have now climbed to eighth place in the Serie A standings. They are trailing fifth-placed Inter by just three points with two more games to go.