Chiellini insists Juve are capable of winning the title this season - but only if they have the mental strength to win the big games.
He said: "Whoever wants to stay at the top must win games with another spirit.
"We didn't show the right attitude against Fiorentina in the first 30 minutes.
"A week ago Milan played badly but managed to beat Fiorentina."
Asked for a reaction to his goal, Simone Pepe said: "When I saw the ball go in I said to myself: 'Come on, let's go and win'.
"It's still too soon to talk about the Scudetto, but we must think big."