Monza coach Raffaele Palladino was delighted after victory at Inter Milan.
Luca Caldarola struck a second-half winner for the minnows.
Palladino later said: It was an incredible feeling to come here and play against an Inter in good shape, that was highly-motivated and fresh from the Champions League, we played with great focus and made the most of the few chances we had. I am proud of these lads and told them we have written our names in history by winning at San Siro,.
I can only thank the club that put its faith in me, the players and my staff. I thank everyone."
Monza GM Adriano Galliani, formerly of AC Milan, motivated the players with a speech before kickoff.
Palladino added: Obviously, this was not a game like the others for him, he told me that he wanted to get a few points at San Siro in his old home. I often give the final speech to the team in the locker room, this time I wanted Galliani to do it, as nobody more than him could fire us up.
We dedicate this win to him and above all to President Berlusconi."