The Rossoneri scored two goals in the final three minutes to give Seedorf his second consecutive league win as manager of the club.
"I am very, very happy for the lads, as it was important for morale to get a victory this way," he told Sky Sport Italia. "We should've scored at least once in the first half and being behind brought out our team spirit. That spirit is the base for everything else.
"Balotelli did very well helping out in defence and everyone fought hard. They all tried to do what we prepared in training and then we created a great deal in attack. It wasn't always pretty, but with such a strong wind factor in the stadium it wasn't easy.
"We held on until the end and maintained our belief, which really pleases me and is important for the next games. When the opposition keeps the pressing on constantly, it is normal to be more dangerous on the counter-attack. I don't think it's just Milan who does that at the moment. We are working on improving matters, but the most important thing was to rediscover mental strength and courage, which we saw today."
Milan are currently ninth in the Serie A table.