Chelsea defender David Luiz has admitted that criticisms affect him from time to time but insists that he is "strong enough to change things".

The Brazilian centre-back has often faced criticism for his performance since joining the Blues from Benfica in 2011.

"No-one likes criticism," the Daily Mail quotes the 25-year-old as saying. "It gets to you and you don't like it and you ask, 'Why are they saying this? I tried my best, why can't they see I'm trying?' It's natural to think like that.

"You can have moments where you're down but you can't let them last. They have to pass. I can be sad for one or two hours but the rest of the day I need to be happy because the team needs me to be positive. My brain needs it. I need it.

"It does get to me. I am not always happy when I see the criticism, and I do care because this is my job. But I'm a positive person. In the end, I know all the difficulties in your life you can change. You can do something about them. When you experience difficult moments, I know I'm strong enough to change things and move on."

Chelsea are currently in Japan for the 2012 FIFA Club World Cup.