Milan, who notched up their fourth win in a row and are seventh with 27 points, needed only 35 seconds to take the lead against 18th-placed Pescara as Antonio Nocerino tapped in at the far post from Stephan El Shaarawy's cross.
In the second half, Elvis Abruscato and Jonathas both headed into their own goal before El Shaarawy, the Serie A leading scorer, got his 14th goal of the season. Christian Terlizzi replied for Pescara.
Juventus extended their Serie A lead with an embarrassingly easy 3-0 home win over Atalanta while rivals Napoli blew their chance to go second with a dramatic late collapse at home to Bologna.
Napoli appeared set to overtake Inter Milan when Uruguay forward Edinson Cavani put them 2-1 ahead in the 70th minute with his 12th goal of the league season.
Instead, Panagiotis Kone levelled with one of the goals of the season in the 86th minute, meeting a cross with an acrobatic volley from just inside the penalty area.
Napoli's stunned coach Walter Mazzarri was still absorbing that blow when Daniele Portanova got in front of the defence to head another in the 89th minute and give Bologna a 3-2 away win which kept their opponents third with 33 points.
Manolo Gabbiandini had given Bologna a 10th minute lead and Alessandro Gamberini levelled from close range five minutes after halftime.
Roberto Donadoni's Parma also won 4-1, at home to Cagliari, while Sergio Pellissier's 87th-minute goal gave Chievo a 1-0 win over sixth-placed AS Roma in fog-bound Verona.
France Under-20 international Ishak Belfodil scored twice as Parma came from behind to beat Cagliari 4-1 while Argentine trio Mario Paglialunga, Gonzalo Bergessio and Lucas Castro scored in Catania's 3-1 win at home to Sampdoria.