On 5 September 2020, Monza played a friendly against Serie A side AC Milan, at the San Siro.

[2] Silvio Berlusconi, Monza's president, and Adriano Galliani, the club's chairman, were formerly part of Milan.

[3] In the 23rd minute, Mattia Finotto leveled the score after beating goalkeeper Antonio Donnarumma one-on-one.

[3] Three goals by Daniel Maldini, Pierre Kalulu, and Lorenzo Colombo gave Milan the 4–1 win.

[22] In December drew Monza 1–1 to Vicenza in a match postponed due to the COVID-19 pandemic,[23] and then lost their second game of the season away to Reggiana in a 3–0 defeat.

[45] Monza began April with two 1–1 draws to the two bottom-placed teams, Virtus Entella and Pescara,[46][47] and a 1–0 defeat to 17th-placed Ascoli.

[49] In May, fourth-placed Monza played their last four games of the regular season against Salernitana and Lecce, respectively in third and second place, Brescia and Cosenza.

[50][51] They finished in third place in the regular season, after beating Cosenza 3–0 and losing to Brescia 2–0, qualifying to the promotion play-offs semi-finals.

[52] Having finished the regular season in third place, Monza gained direct access to the semi-finals of the promotion play-offs.

[104] Despite being reduced to 10 men in the 41st minute, after Edoardo Colferai received his second yellow card, Monza held on to a goalless draw, with the scoreline remaining the same after extra time.