The 24th minute goal of Giacomo Raspadori was enough to achieve a crucial three points in front of Antonio Conte.
Napoli remains at least three points free from Inter Milan in the race for the Serie A title with Simone Inzaghi's side in the late kick-off of Helles Verona.
After the game spoken with the press, Conte finally admitted that his side looks good for the title, but warned them to face themselves.
“I don't have to lie, this was an important step in the direction of the Scudetto,” Conte told Dazn.
“It is an important step, even though it is not the most important. I was afraid of Lecce on their own turf, because they are fighting against relegation, while we arrived here who deal with an emergency situation.”
The Italian almost stormed off the tunnel as soon as the last whistle went: “I ended the game stressed, not angry,” he explained.
“I will say if and when it happens, because on the last day I won both titles and lost. Those who win write the history books. The others can only read them.”