Ivan Perisic's 92nd-minute strike has denied AC Milan the chance to move into second place in Serie A after Inter Milan fought back to draw the Derby della Madonnina.
The Nerazurri started strongly at San Siro and had chances to take an early lead through Perisic and midfielder Geoffrey Kondogbia.
Inter then wasted their best opportunity of the first half on 24 minutes when Danilo D'Ambrosio's cross found Perisic at the back post, but the Croatian attacker was unable to beat keeper Gianluigi Donnarumma.
Milan then made their city rivals pay for their profligacy three minutes before the interval as Suso found space to deliver a left-footed shot, which left Samir Handanovic beaten and gave the Spaniard his first goal at San Siro.
On 53 minutes, Inter produced a stunning equaliser as Antonio Candreva struck a fierce right-footed effort beyond the reach of Donnarumma.
However, Milan quickly restored their lead before the hour mark after Suso weaved his way through the Inter defence and deftly passed the ball beyond Handanovic.
The Nerazzuri almost responded with a second on 69 minutes when Mauro Icardi managed to get himself in front of Gustavo Gomez and, with the offside flag still down, the Argentina forward failed to connect with ball from close range.
With Milan seemingly destined for victory in the derby and set to reduce Juventus's seven-point lead in the table, Perisic ghosted in at the back post from a stoppage-time corner and beat Donnarumma from a few yards out.
