Napoli lacked a finishing touch in Saturday's 0-0 Serie A draw against relegation-threatened Hellas Verona, coach Luciano Spalletti said after the league leaders had only one shot on target.
Napoli have scored more goals than any team in Serie A this season but have now failed to find the net in three of their last four games in all competitions.
"We had less quality than ever, we created some space but we were not good at playing in that space," Spalletti told a news conference.
"A lot of difficulties came from the performance of Verona, a team accustomed to goofing around, even wasting time as they did tonight. We found a team that closed in spaces. We were not good at playing in that space, we didn't have the quality we usually have," he added.
However, the goalless match was marked by the long-awaited return of top scorer Victor Osimhen, who had been sidelined with a thigh strain.
"He needed to regain confidence. In the last 25 minutes he has shown that he has greater potential than the others," Spalletti said about his decision to bring in the striker who missed this month's league games against AC Milan and Lecce.
"Victor brings strength and enthusiasm to the team. He has a structure and a physicality for which you can play with the ball and at the same time he is capable of closing on the net,"
After the 1-0 defeat to Milan in the first leg of the Champions League quarterfinal on Wednesday, Spalletti's side face a major challenge at home, when they face the Italian club again for the second leg.
"On Tuesday it will take our quality, the right tactical attitude and the drive of our fans, like tonight's," Spalletti said.