Dries Mertens and Lorenzo Insigne impressed again, while Allan made his debut as Napoli beat Lega Pro side Feralpi Salò 5-2.
Coach Maurizio Sarri continued to experiment with different systems and the need for reinforcements in defence is clear.
Jose Callejon was used as a ‘False 9’ in attack, flanked by Insigne and Mertens.
Insigne has been on sparkling form so far this summer and his curler was parried into the path of Mertens to open the scoring.
Kalidou Koulibaly turned in from a corner moments later, but Feralpi Salò surprisingly found the net too following a defensive error.
Insigne unleashed a screamer into the top corner before Marek Hamsik’s through ball allowed Mertens to dribble round the goalkeeper.
Ex-Udinese midfielder Allan made his Partenopei debut for the final half-hour, while Omar El Kaddouri had several good chances.
Jonathan De Guzman added a fifth goal from Gokhan Inler’s assist, but once again the defence was caught out late on from a set play.
Napoli 5-2 Feralpi Salò
Scorers: Mertens 10, 40 (N), Koulibaly 12 (N), Romero 30 (F), Insigne 34 (N), De Guzman 83 (N), Guerra 87 (F)
Napoli: Gabriel (Rafael 46); Maggio (Henrique 46), Albiol (Luperto 67), Koulibaly (Allegra 75), Ghoulam (Dezi 78); David Lopez (Allan 61), Jorginho (Inler 46), Hamsik (Valdifiori 46); Insigne (El Kaddouri 58), Callejon (De Guzman 58), Mertens (Gabbiadini 46)