The veteran was on the scoresheet in the 3-2 loss.
"Normally it would have been a draw," said Thiago Silva to the club's website.
"It's not like West Ham created lots of opportunities, we gave them two goals. We have to take more care because that's two or three matches now where we have given the opposition a goal.
"But we played okay, we kept the ball well and tried to control the match. The first and third goals were a bit unlikely, a bit difficult to explain. I don't think the third was a shot, he was trying to cross the ball and it went in the goal.
"It's the first time this season we have conceded three goals in the same match.
"We played much better than we did in the game before [at Watford], but a team on our level can't allow them to win a match like that, one we had under control. It's difficult to take this defeat but we must keep our heads up."
On conceding three goals, he continued: "It's not only physically difficult this league, it's mentally difficult. There are a lot of matches at the moment, a lot of injuries, not just for Chelsea, and it's the most intense league in Europe.
"You have to make changes, and you can pay a little bit for that, but it's not an individual sport, it's a collective one. We must keep our head up and get ready for the next match that's coming, because we can't change what's happened, but we can change the future."
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