The Blues centre-back has been through a difficult few seasons, suffering a serious knee injury in 2016.
But he shone on loan at Everton last season, which earned him another chance at the Stamford Bridge club.
Now he wants to make sure he irons out the flaws in his game.
He said to reporters: "Myself, I knew I made mistakes in the first game but it won't be perfect every game. You have to learn from games. I am still learning.
"After a game like this, you just have to refocus, keep the concentration high and then I think I did right after that by keeping myself ready and prepared.
"We don't get the wins but me, I give it my all on the pitch. That's what I'm here for."