Barca won 14 trophies in four years under the guidance of Guardiola, and former
Milan coach, Sacchi reckons Vilanova will find it hard to equal the unprecedented period of success.
"I like Tito Vilanova, but, I think it will be difficult for him to repeat what Pep did," admitted Sacchi.
The Italian also questioned the signing of Alex Song, who was brought in from Arsenal for £15m during the summer.
"[Song] is a very good player, but Barca already have Busquets and Mascherano who can play in the same position, so I am not sure about this signing."
Next up for Vilanova's side is a trip to Real Madrid for the second leg of the Supercopa, where the Catalan side lead 3-2 from the first leg.