Sheffield Wednesday boss Carlos Carvalhal has said he takes "all the responsibility" for his side's Steel City derby defeat by Sheffield United.
The Owls fell to a 4-2 loss at Hillsborough on Sunday.
"Today was not normal. I don't remember the last time we conceded four goals and we made mistakes I had not seen us make," he told BBC Radio Sheffield.
"I'm the coach and I'm responsible. We need to react fast because we had been doing well before today."
He added: "The first goal made us more nervous than normal and we started making mistakes that we would never do.
"The good thing was the heart and character we showed to get back to 2-2 and everyone thought we would win then but then we conceded again."
In the first derby in over five and a half years, the Blades were 2-0 up after 15 minutes thanks to goals from John Fleck and Leon Clarke before Gary Hooper and Lucas Joao levelled the scores.
However, just one minute and 47 seconds after Joao's goal, Mark Duffy put Sheffield United back in front and Clarke's late second sealed the three points for the visitors.
'This was the big present'
Sheffield United, who won promotion to the Championship last season, are up to fourth in the table.
Manager Chris Wilder, who is a Blades fan, turned 50 on Saturday and was delighted with his side's performance.
"I got a couple of bottles of aftershave, the odd jumper, a box of beer but this was the big one," he told BBC Radio Sheffield.
"I'm blown away with the occasion because I never got to play in this derby. It was a tremendous occasion and I thought we thoroughly deserved the victory."
He added: "We wanted to come here and win. This is everything. Nobody can tell me this is just another three points because it isn't."