Matteo Politano scored the match’s only goal provided by a perfectly-weighted Piotr Zielinski through ball as the visitors took advantage of Milan midfielders’ errors.
“This is not the game we prepared, it was not what we intended to do. Napoli closed down all the spaces and we didn’t create enough scoring opportunities,” Tonali told Sky Sport Italia.
“The ones we did create with Rafa Leao were not converted and then Napoli scored their first real chance.”
Fallen far from Inter at top of the table, the 20-year-old still believes his side must aim high to reach success.
“I don’t think there is fear, otherwise we’d lose every game. We are here, we must continue to aim high and not give up now.”
Joining the Rossoneri from Brescia last summer, Tonali has become a key part of Pioli’s squad this season.
“I took a while to get going, as I hadn’t played for some time before coming to Milan. I knew this would not be an easy path, but it is the right one and I am starting to feel consistency, which is the most important thing for any player.”
The Italian also got in charge of his side’s corners and free-kicks due to Hakan Calhanoglu’s absence.
“The coach and the staff study us and we study the set-piece routines they propose to us. Any set play can become a scoring opportunity, so they are very important.”