Mauricio Isla scored the only goal of a dramatic game which saw both teams miss a penalty and both end the game with 10 men.

Javier Zanetti was first to go when he gave away a penalty which was saved by Julio Cesar, while Damiani Ferronetti followed him into the dressing room a minute later after giving away a penalty which Giampaolo Pazzini missed at the other end.

Inter therefore succumbed to their sixth defeat of the season to fall 13 points behind their opponents and their city rivals.

Napoli warmed up for their vital Champions League tie with Villarreal by brushing past basement boys Lecce 4-2.

Knowing that a win over the Spaniards will see them through to the knockout stages of the tournament, Walter Mazzarri's men ensured they will head into that clash full of confidence thanks to this four-goal show at Stadio San Paolo.

They may have some concerns over their defence, though, with Luis Muriel and Daniele Corvia scoring for Lecce, although those goals were only consolations at 3-1 and 4-2.

Ezequiel Lavezzi, Edison Cavani (two) and Blerim Dzemaili had already put the game out of sight for the home side.