The Spaniard signed for Chelsea in a £75m deal, but so far has not contributed as many goals to the cause as fans were hoping.
"Morata is a quality player, fast and technically gifted. He's a sensitive person and the difficulties had hurt him," Sarri said to 'DiMarzio'.
"The results and the quality of our football are positive. 18 games without a loss, in such a competitive reality show that we're on the right track."
The Italian manager also defended another of his players, David Luiz. The Brazilian defender has often been caught out due to a percieved lack of discipline. However, Sarri was surprised by Luiz's approach.
"There isn't a lot of time between the training sessions and I think it doesn't help the coach nor the players," he added.
"It's not even only about the physical aspect but also about the mental one. David Luiz surprised me by his availability and cleverness."