Alvaro Morata claims he has overcome the mental torment of his debut season at Chelsea.
Sarri admitted he had concerns about Moratas mental toughness, and wants to see his centre-forward continue to improve.
Moratas debut season at Chelsea fell apart thanks to injury and poor form, and the Spaniard revealed he used to blame the rain for missing chances.
Im better, Morata said. I think no one, only my wife, knows how big the last year was.
The injury, it killed me. Now, its OK. In the last month of last season, I was down, down, down, down. I cannot be more down.
When you touch the limit, the only thing you can do is to come back.
I had a period where, if its raining, Im angry because its raining. If I miss, its because the pitch is too wet. It was only excuses. It is not good.
Everyone can have a bad period in their life. But we are famous, we have a lot of things. Sometimes people think we are not human, with no feelings, no problems.
The important thing is to find the right balance. Now, I have, and I am very happy.
Morata has bagged four goals in his last four Premier League appearances, and Chelsea fans are hoping 26-year-old can find consistency in front of goal.
Chelsea were rumored to want to offload Morata in the summer and have been tipped to sell him in January, but the forward insists he is now on top of the mental side of his game.
It takes time. Because I had an injury, I was not fit when playing. But now I feel good, Morata continued.
The most important thing is that, finally, I have found the right way and my head is OK.
In football, physical condition is very important, but the head is the most important thing. If you dont have the head, if the mentality is not good, then you are in trouble.