The Spain international remained at Stamford Bridge beyond the summer transfer window despite a difficult end to the 2017-18 season.
Morata scored three goals in his final 29 games under Antonio Conte to raise questions about his future after falling behind Olivier Giroud in the pecking order.
The 25-year-old striker was given the chance to prove himself in the Blues team following Sarri’s appointment as Conte’s replacement in July.
Morata has netted five goals of Chelsea FC’s 30 goals in the Premier League this season ahead of their trip to Wolves on Wednesday night.
The Spanish forward has struggled to find consistency in the current campaign despite some positive performances to suggest Morata was about to turn a corner at Stamford Bridge.
Sarri revealed that building up Morata’s confidence is the key to maintain the striker’s form in front of goal.
“Alvaro has scored four or five goals in the last seven matches,” Sarri told his pre-match media conference at Cobham on Tuesday afternoon. “I cannot see a big problem.
“Alvaro in every season scores 15 or 16 goals, not more. I hope [he scores] more this season, but at the moment we are on his average. I can give him confidence. I can speak with him every week. Then, on the pitch, you are alone.
“I have to understand very well what he needs but I am unable to do everything. Morata in the last month played well, he scored goals and he needs only continuity I think. He needs confidence and confidence and confidence. We need only to have continuity in scoring.
“Now he is 25, I think he can change but his character is this so he has only to stay calm. In the last match he missed the goal only because he wanted to score too much.”
Morata moved to Chelsea FC in a £60m deal from La Liga giants Real Madrid in the 2017 summer transfer window.
The Spanish forward arrived in west London having won domestic titles with Juventus and Real Madrid, as well as the Champions League twice with los Blancos.
Morata has never scored more than 15 league goals in a season to highlight that the striker isn’t a prolific goal-scorer.
MORE: Man United latest news
MORE: Arsenal latest news
MORE: Chelsea latest news
MORE: Liverpool latest news