Lautaro Martinez’s header was enough for Inter Milan to beat city rivals AC Milan in the Derby della Madonnina at the San Siro.
The Argentine, who captained the side on the night, headed the only goal of the game from a corner by former Milan midfielder Hakan Calhanoglu.
Second-placed Inter remain 13 points behind Serie A leaders Napoli, who won 3-0 at Spezia earlier in the day courtesy a Victor Osimhen brace with Georgia winger Khvicha Kvaratskhelia converting a penalty.
Inter had two goals disallowed late on – substitute Romelu Lukaku’s effort was ruled out for a foul on Malick Thiaw and a long video assistant referee decision upheld the decision to rule out Argentina striker Martinez’s effort because he was offside when he latched onto Lukaku’s flick to slot home.
Milan, who dropped to sixth in Serie A this weekend, have lost five of their last six games in all competitions.
Stefano Pioli’s side did not manage a shot on target until the 75th minute, when Andre Onana denied Brahim Diaz.