Chelsea boss Frank Lampard says they must learn from defeat at Everton.
A penalty conceded by goalkeeper Edouard Mendy and converted by Everton's Gylfi Sigurdsson separated the two teams.
Lampard said, "It was tough, it was a tough night for both teams, the difference was they got the early goal and stopped up playing after that.
"After that we found it too hard to break them down. We didn't play well."
On Mendy after he conceded the penalty shortly after getting injured, he added: "I don't know he got caught in the middle a little bit. He has been incredible since he has ben here, I just think it was one of those.
"It was absolutely the game we expected and I expected. I expected the style of the game, the unity, the fans back in the ground.
"We are a young squad, new players that haven't won leagues. Sometimes you learn on your feet and tonight was one of those games.
"I am not going to criticise, when you have an off night you rely on other things like keep a clean sheet and then Mason's free kick goes in off the post, not the other way round."
