President Massimo Moratti's side had a host of injuries, including Diego Milito, Maicon, Walter Samuel, Thiago Motta, and Christian Chivu, so Javier Zanetti slotted in at left-back while Esteban Cambiasso returned to the midfield. Meanwhile, veteran midfielder Luciano was the only notable absence for coach Stefano Pioli as four points separated these two sides at the start of play.
Goran Pandev should have opened the scoring on 13 minutes, Samuel Eto'o collected on the edge of the area and poked through for the Macedonian, who rounded the goalkeeper but hit the post from a tight angle.
Flying Donkey's captain Sergio Pellissier wasted a promising counter and at the other end Wesley Sneijder's curling freekick required a decent save from Sorrentino.
In a goal out of nowhere, Pellissier put Chievo ahead 1-0. The cross came in from Nicolas Frey on the right and the veteran ran in unchallenged and lept above Davide Santon to power an unstoppable header past Castellazzi with just under 30 minutes gone.
Inter were shaken by the goal and Eto'o and Bostjan Cesar got into a scuffling match which eventually resulted in a reaction from the Cameroon international, who headbutted the Slovenian defender in a Zidane-like incident, but it went unpunished though the frustration was clearly getting to the Nerazzurri. A ban by video evidence is likely for the former Barcelona star.
In first-half injury time Pellissier came close to his second goal after finding space in the area, as the half ended 1-0 for the Flying Donkeys.
Inter came out more determined in the second-half, but Stankovic was required to clear the ball off the line after Luca Rigoni's header following a corner kick. Cambiasso could not continue on his comeback to the line-up and was replaced by Obiora Nwankwo in midfield.
The visitors were struggling to find any way through Marco Andreolli and company at the back. Stankovic had dramatically improved in the second-half and almost caught Sorrentino off his line with an imaginative lob with just over an hour past.
The Flying Donkeys could have put the game to bed, but Gelson Fernandes missed an open goal after Castellazzi couldn't hold Kevin Constant's powerful volley. Sorrentino then made a miraculous reaction save on Eto'o's toe poke on the opposite side of the pitch.
With 15 minutes left, the Nerazzurri desperately began to pour men forward in search of an equaliser. Substitute Denis Alibec and Eto'o played a fantastic one-two through the defence, but the latter failed to get the decisive final touch.
Chievo made them pay with ten minutes left as a long ball over the top found Rigoni, who had all the time in the world to control and cross to Moscardelli for the knockout punch and a 2-0 scoreline.
Eto'o scored his league leading ninth of the season as a late consolation, but it simply wasn't enough from last season's treble winners.
The result leaves the Nerazzurri nine points adrift of Serie A leaders Milan and also behind Lazio, Napoli, Roma, and Juventus in the table.