Victor Osimhen’s header on a Hirving Lozano cross proved enough for Napoli, as Bologna woke up too late to get back into the game.
The Partenopei had a couple of early chances, Dries Mertens knocking down a Hirving Lozano cross for Insigne, then on the resulting corner Insigne’s ball flashed across the face of goal with nobody getting the final touch.
Chucky Lozano was in fine form and he created the goal with a floated cross to the back post for totally unmarked Osimhen’s cushioned header.
It was the 40th consecutive Serie A game without a clean sheet for Bologna.
Napoli thought they had doubled their lead after the restart when the Nigerian attempted an overhead kick on a corner and Koulibaly was quickest to react on the rebound.
However, after an on-field VAR review, it was confirmed the ball had struck Osimhen on the hand, meaning it had to be disallowed.
Bologna woke up too late, but continued to frighten the Partenopei but to no avail.