Cardiff boss Neil Harris laid into his struggling side after they conceded a "shambles" of a goal to slip to a 1-0 defeat at Coventry.
Cardiff, play-off semi-finalists last season, sit 18th in the Sky Bet Championship with just one win in eight after Tyler Walker's strike handed Coventry a vital victory at St Andrew's.
Walker pounced to net the winner in the 54th minute after a mix-up between skipper Sean Morrison and goalkeeper Alex Smithies, who had made several saves to keep Cardiff level.
"That wasn't good enough," admitted Harris. "The goal sums us up, we were masters of our own downfall.
"We gave the ball away cheaply and the goal was a shambles. I was quite aggressive in what I said to the players after the game, I showed my disappointment.
"We have a talented group of players who need to show they want to play for the club more.
"The responsibility falls with me, I pick the team. I have no issue with that, results are based around what the manager does but you need your players to perform as well.
"Today as a group, we weren't good enough, it hurts me to say that. It was below par, we have to be better.
"It's a disappointing start, we don't have as many points as we expected but I don't have to listen to anyone else, I judge myself. I take responsibility for results and the changing room."
Coventry, meanwhile, have kept back-to-back clean sheets, although they were relieved to see a first-half own goal ruled out for a push by Morrison.
Walker netted for the second time in three games as he continues to deputise for injured top scorer Matt Godden and Sky Blues boss Mark Robins was delighted with his side.
"The biggest pleasing thing for me was the clean sheet but also the way we went about the job – we showed a brilliant aptitude for a fight," he said.
"They've got some brilliant players and we've limited them to very little, and credit has to go to the whole team for that.
"I think Tyler Walker's work-rate was phenomenal. His goal was outstanding and he grew in stature and confidence throughout the game.
"We needed the clean sheets because we were shipping too many goals and in these two games it's been particularly important with the amount of crosses that come into your box."
The only downside of the night for Coventry was a fractured cheekbone suffered by goalkeeper Marko Marosi in an injury-time collision with Morrison.
Robins added: "Hopefully he's going to be okay quickly but he was in a bad way after the game and we've got to get him off to hospital."