The two Premier League giants played out a tough game at Stamford Bridge, which the Blues won 2-1.
Despite Sanchez not having the best of control over his passes, he did put in a solid display in goal.
Maresca stated post-game: "He also did so many good (things). In the end, that is football. I am the guy who asks Robert to do that. And Robert is going to do that. In the moment he stops to do that, he is not going to play.
"If Robert makes a mistake, it's not Robert's problem, it's my mistake because I asked that from Robert. I am very happy with Robert and the way he is playing, building from the back. All the goal kicks we have and he passes the ball to Noni, and Pedro, that kind of ball that gives us many times chances to attack. Sometimes you make mistakes but it is not going to change the way we are going to play."
On midfielders Moises Caicedo and Romeo Lavia, he added: "Romeo and Moi did very well. Enzo was inside but overall, I'm very happy with the performance today. For some moments on the ball we were unbelievable, some good combinations. The way we prepared the game, the plan, it was exactly there.
"Off the ball we fight together, they deserved three points. That's important."