Napoli beat Sampdoria 2-0 ahead of their Champions League meeting with Liverpool on Tuesday.
Carlo Ancelotti's side host the European champions in their opening Group E fixture next week and, like the Reds, go into that game on the back of a domestic victory.
Dries Mertens scored in either half to defeat Sampdoria at Stadio San Paolo on Saturday evening.
Speaking post-match, Ancelotti said: "It was a good display and we deserved the win.
"It was important to impose our game and keep a clean sheet as well. In the first half, we made a few mistakes bringing the ball out which allowed them to break.
"We then became more compact and controlled the game. We certainly took some risks, but that's also down to our attacking style. I think the fans enjoy it more that way.
"I opted to play Fabian [Ruiz] centrally to help us have more possession. Having [Piotr] Zielinski in the holding role is useful because of his long passing and I think he likes to attack the space.
"We can breathe a sigh of relief because we've finally kept a clean sheet, but we still need to improve defensively."