Insigne was linked with Barcelona in the final days of the transfer window and said that a switch to the Blaugrana would be a dream, while also lamenting Napoli's failure to win major trophies despite an impressive squad.
For now he remains with Napoli, though former Italy and AC Milan coach Sacchi feels Insigne would be a perfect replacement for Neymar after the Brazilian's world-record move from Barca to Paris Saint-Germain.
"I don't think Barcelona are up to the same standard as Real Madrid," Sacchi told La Gazzetta dello Sport.
"Having lost Neymar, Insigne would've been the perfect replacement. He is the greatest Italian talent in 10 years and has some genial intuition.
"He just needs to avoid being 'sneaky' when he isn't in the mood to run.
"When Dries Mertens and Marek Hamsik block the midfielders who can only go via the right-back, he looks back and tries to make preventative blocks instead of trying to snatch the ball.
"It's a shame, because tactically he really is wonderful."