In a match which pitted top against second and saw the division's two remaining unbeaten sides go head to head, neither could break the deadlock as they both drew blanks for the first time this season.
The result brings an end to Napoli's eight-match winning streak to start the season and their nine-match winning run at home, although they remain two points above Inter at the top of the table.
The hosts were the first to threaten when Dries Mertens worked space to shoot from the edge of the box, but Samir Handanovic denied the Belgian before recovering in time to also keep out the rebound from Jose Callejon.
Handanovic was in action again with 10 minutes remaining of the first half, although this time it was a more routine stop as he comfortably gathered Lorenzo Insigne's header from inside the box.
Inter had to wait until the 42nd minute for their first really clear opening when Mauro Icardi - hat-trick hero from Inter's victory in the Milan derby last weekend - found space inside the box, but Pepe Reina pulled off a fine save to deny the skipper.
Icardi came close again in the opening stages of the second half, but this time it was a defender who blocked his effort from close range as Napoli survived.
The defence came out on top throughout the remainder of the contest too as both sides struggled to create meaningful goalscoring opportunities and were forced to settle for a point apiece.
Both teams remain unbeaten in the league this season due to the draw, and the result also ensures that they will end the weekend as the top two regardless of results elsewhere on Sunday.