Sassuolo move up to 11th after beating Intermilan 2-0
Substitutes Edin Dzeko, Lautaro Martinez and Alexis Sanchez were among those who failed to capitalize on scoring opportunities as Inter stepped up the pressure in the second half.
Milan are without playmaker Marcelo Brozovic who is suspended.
Stefan De Vrij eventually emerged to pull back at least one goal for Inter in second-half stoppage time but the goal was ruled out by VAR for handball.
Lazio saved a 1-1 draw at Udinese to stay in sixth place