Norwich manager Paul Lambert bemoaned his side's defending after they threw away a half-time lead to lose 2-1 at home to Crystal Palace.
Julian Bennett and Anthony Gardner headed in from corners to cancel out Grant Holt's opener and gift the Eagles a victory which saw City slip down to fifth place.
Lambert said: "I'm very disappointed to have lost a game to two set-pieces, that is not like us at all.
"It's something you work on on the training ground all the time but that's no good if you don't go out and do it properly on the pitch. We didn't defend properly at two corners and got punished for it.
"The two lads who were missing from the defence (Adam Drury and Elliott Ward) have been colossal for us this season but that doesn't wash with me as an excuse.
"It's about the squad and all the players should be able to do the same thing at set-pieces."