Goals in each half from Pierre Kalulu and Tommaso Pobega had given the Rossoneri a two-goal lead, but Roger Ibanez and Tammy Abraham scored in the closing stages to leave the Milanese giants trailing Napoli and Juventus in the Serie A standings, after they both won earlier in the weekend.
AS Roma fail to impress for 85 minutes
Straight from kick-off, Roma clearly planned to frustrate their hosts and disrupt their game. With Bryan Cristante and Zeki Celik booked inside the opening 10 minutes for tactical fouls, and the team refusing to be drawn into pressing the Milan defence when in possession.
A disciplined Giallorossi refused to let Milan in behind their own back line, so it was the 29th minute before the Rossoneri had a shot on target. Brahim Diaz fired a drive from the edge of the box straight at goalkeeper Rui Patricio, who palmed comfortably over the crossbar.
However, from the resulting corner, the Portuguese shot-stopper was at fault. Flapping at a header from the poorly marked Kalulu and watching the ball spin agonisingly into the net. Going behind did not deter the side from the capital, though, who continued with their cautious approach until the break.
AS Roma leave it late
While Milan started the second period more positively than the first, the visitors again forced them into speculative efforts from distance. Rafael Leao sent a powerful drive into the upper tiers of San Siro shortly after the break and Patricio fumbled a long-range Theo Hernandez strike.
On 72 minutes, Alexis Saelemaekers even tried to win a penalty for his side by craftily lifting the ball onto the hand of Roma defender Roger Ibanez, but the referee refused to be deceived by the attacker. The Belgian need not have worried, though, as moments later the Rossoneri broke away and Pobega curled a low shot past Patricio.
However, on 87 minutes the visitors found the back of the net when Ibanez headed home a Lorenzo Pellegrini corner kick and, when Ciprian Tatarusanu failed to deal with a similar effort three minutes into added time, Abraham reacted quickest to slam home the equaliser.