Arkadiusz Milik scored twice on the day.
“At this moment, it is important to show solidity and maturity, both of which I saw this evening," Ancelotti told Sky Sport Italia.
“On a tactical level, at times when defending 4-4-2, we don't have the right timing of our movements and can push the full-backs forward too quickly, which leaves gaps. We were already in the lead in the second half and therefore not so hasty to pour forward."
Milik hadn't scored at all for Napoli this season, but after a stunner for Poland midweek, he netted a brace.
“I think the goal he scored on international duty was the key, the switch that changed the chemistry of his mood and confidence. He had some fitness problems, has recovered and is regaining his form."