Dani Mota Carvalho: AC Milan lost to Monza for the first time as they suffered a 4-2 away defeat in Serie A with Luka Jovic seeing red.
The Rossoneri were coming off a 3-0 Europa League win over Rennes and rotated their line-up for Sunday's game.
Monza surged into a 2-0 lead in a matter of minutes before half-time, as Matteo Pessina converted a penalty before Dani Mota Carvalho finished with a curling effort, reports Xinhua.
Milan's situation went from bad to worse straight after the break as Jovic was sent off for slapping Armando Izzo.
However, the away side got one back as Christian Pulisic flicked on for Olivier Giroud to tap in from close range, and Pulisic's left-footed strike went beyond the out-stretched Michele Di Gregorio in the 88th minute.
But Monza ruined their opponents' hopes in the dying minutes when Milan loanee Daniel Maldini assisted for Warren Bondo to drill home from the edge of the box, before fellow Milan-owned player Lorenzo Colombo sealed the game.
The setback saw Milan fail to overhaul second-placed Juventus, as they still rank third with 52 points.
Elsewhere, Roma dominated Frosinone 3-0 thanks in part to Dean Huijsen's sensational solo goal. Lazio, who had stunned Bayern Munich in the Champions League in midweek, lost to Bologna 2-1. Udinese drew with Cagliari 1-1, and Empoli and Fiorentina also played out a 1-1 draw.