The 32-year-old defender was speaking after their friendly defeat to Tottenham.
“Spurs? We went into that game from three, demanding weeks in the US and two days of days of intense training,” Chiellini told La Stampa.
“I was expecting us to struggle, but it was better to face a team that played with intensity. Bonucci? Pirlo and Vidal also left, as did Pogba… It takes a while to adapt without them and you also have to wait for the new signings to settle.
“Maybe we’ve lost something from our game, but we have the best attack. Maybe Pjanic will drop back a bit. We needed a slap in the face, to wake up from the slumber. The objective is to be ready for the Supercoppa. We’re better now than we were last season.”