However, instead of shooting, the youngster tried to tee up Edinson Cavani, only for his pass to be intercepted.
That error was punished by in-form starlet Stephan El Shaarawy, who went on to bag a brace to rescue a point for the Rossoneri.
"It's a shame, as with a little more sharpness we could've closed it," Football Italia quotes the 51-year-old as saying. "We needed to control the tempo better, but instead we even took free kicks quickly.
"When a team takes the lead and doesn't finish off the game by wasting chances [like Insigne's], then against a side like Milan you're inevitably going to end up with a draw.
"We need to improve and work on these aspects of the sport. We could've also done better on the counter-attack, but instead we threw away two points."
Napoli sit third in Serie A.