Jose Callejon's first-half goal condemned Inter to a sixth consecutive winless game as Napoli earned a 1-0 victory at San Siro on Sunday.
Callejon scored his 11th strike of the league season shortly before half-time but the visitors could have made the result more emphatic had they capitalised on a poor defensive performance by Inter.
Following a nosedive in results, Stefano Pioli's position as head coach of Inter was the subject of intense speculation going into the game and the defeat saw his side miss out on the chance to leapfrog rivals AC Milan into sixth place in Serie A.
Inter now have four games left to save their season, while Napoli's hopes of finishing second and clinching automatic qualification for the Champions League group stages remain very much alive.
After second-placed Roma were beaten 3-1 by Lazio earlier in the day, Napoli's win takes them to within one point of the Giallorossi and the form that has helped them avoid defeat in the league since February is showing no signs of abating.
