Cardiff boss Sabri Lamouchi criticised the attitude of his team as they fell to a 20th league defeat of the season.
The Championship’s lowest scorers are now 21st and only a point above the relegation zone, with Lamouchi warning their survival bid will go down to the final game of the season.
Four of Cardiff’s remaining six games are away, including to champions Burnley and, next up, Sheffield United.
“Bad attitude and bad performance in the first half,” Lamouchi said.
“When you are losing you are always disappointed. But I’m more disappointed about the first half. The second was a little bit better, we faced some situations to come back into the game.
“We can’t concede a goal in the second half like that. We cannot start the game in this way.”
Lamouchi was so disappointed by Cardiff’s performance in their 1-0 home defeat to Sunderland that he hauled off two of his key attackers, Jaden Philogene and Sheyi Ojo after only 35 minutes.
“We made some changes and probably we can make some more changes,” he told BBC Sport Wales.
“The changes were not too early. I probably should have done it earlier. I don’t regret the changes, because I didn’t want to wait until they scored a goal.
“I tried to change the mind of my team and it was the wrong mentality. I must do something before the break, because we were so deep, we were so… I don’t want to say the word, but not so good.
“Jaden [Philogene] and Sheyi [Ojo] need to understand why I was angry, it was not a punishment for these two.
“This is my responsibility, to do something, to try something. We wanted to send a message to the team and the players.
“And probably, if I’m fair, we didn’t deserve more than we got today.”
Lamouchi, Cardiff’s third permanent manager of the season, believes the Bluebirds’ battle to avoid the drop is destined to go to the wire.
“Probably we will need to fight until the last game so we must be ready for that. In one moment I was thinking we were doing well, but we miss consistency,” he added.
“The small details in our level aren’t there at the moment, we need to be more angry and show more character.
“The table was exactly the same two months ago. Unfortunately we didn’t change our position in the table.
“We missed a lot of opportunities and we missed consistency, character and personality.
“We need that if we want to stay in the Championship. We need to think about that and be absolutely honest with ourselves. This club and these fans deserve to be in the Championship next season.
“If you aren’t consistent in the Championship, you deserve to be where you are and you will be there for a lot of reasons.”