The defender scored seven league goals and provided three assists last season, and is off the mark with a goal and two assists in nine appearances for the Blues so far this term.
But his impact was immediate and he played an important role in the Blues' march to the Premier League title at the end of the campaign as a wing-back under Antonio Conte. Now I think the same, but now he's more suited to my football, he's improving.
"It's normally the same questions with [Lionel] Messi, with [Cristiano] Ronaldo".
Chelsea's last match was an acrimonious 2-2 draw with Manchester United that ended in a melee after Sarri's assistant coach Marco Ianni exuberantly celebrated a late equaliser in front of the opposition bench. It's very hard to solve the tactical problem without an improvement in the defensive phase of these three midfielders.
Sarri and Ianni both apologised to Mourinho after the incident and the Italian said he wanted to give his assistant a chance to redeem himself.
"First of all, as I said after the match, we were wrong", Sarri said. "I was there when Marco spoke to Mr Mourinho and he said sorry immediately".
"In the past two seasons he has developed into an important player for the club, demonstrating his outstanding ability and a fantastic attitude that has helped him become a Premier League champion and Spain global".
"I know he's only played 33 minutes, but he's done virtually anything you could ask of him". We were wrong and have to accept the consequences.
"That's why we've been doing so well because everyone wants to do well in training - training is so sharp".