Nottingham Forest boss Sabri Lamouchi apologised for his side's crushing home defeat against Sheffield Wednesday and added: "We cannot accept this."
Lamouchi was furious with the Reds following a performance that went against everything his side had previously produced this season.
Forest had boasted one of the strongest defensive records in the division prior to this game – but that was rarely evident as Wednesday made them look painfully fragile.
Jordan Rhodes had not scored previously this season but had hit the back of the net three times by the 37th minute at the City Ground, as the Owls romped into a four-goal lead before the interval.
Fellow forward Steven Fletcher netted the fourth in stoppage time and was a big influence throughout the game.
"First of all, I just want to apologise about this big defeat, in front of our fans," said Lamouchi. "I am the only one responsible for this. It is a big disappointment for me, for the players, for the fans and their families.
"It was a bad week, not just a bad day. We must learn from this, because today we gave them a lot.
"Congratulations to Sheffield, because they played with quality and experience. They played in the right way. That is it. In the second half, it was different – but it is easy for the opponent to manage the game when you are 4-0 down.
"At the beginning of the season our quality was our defensive aspect. Today it was our big weakness, because we gave them four easy goals and it might have been more. Fortunately it was not.
"I am very surprised. I am shocked. I am ashamed of this performance.
"I am the manager of Forest. This is my responsibility. You cannot give away easy goals like this. The Championship is a tough league, every game is difficult.
"It is not an excuse. I am not afraid to use strong words. This is my first time apologising to Forest fans and I hope it is the last. We cannot accept this.
"You can lose, that happens in football. It is not about the result, it is about the performance, the attitude, the intensity – the simple details."
Sheffield Wednesday boss Garry Monk praised Rhodes for his hard work and toil – which he believes provided the foundations for his spectacular hat-trick.
It was the Owls' ninth win from their last 10 meetings with Forest, and Monk said: "I am delighted for Jordan – we all are. It has been tough for him.
"In the last couple of seasons and into this season, it has been tough for him.
"But I spoke to him when I came in and I just asked him for hard work. I understand what he is, but he has had to be patient. I told him he would get his opportunity and, when that opportunity came, that his hard work would pay off.
"We always knew he had quality, But he has pushed his way back into the team and here he took his opportunity.
"He just needed to keep his confidence and belief. I know it has been tough for him, he has had to work his way back in. But he trained to a high level and he has shown his personality.
"This was an accumulation of everything for him. A fantastic performance and three great goals for him."
Monk felt Wednesday's game plan worked to perfection, as they took three points that lifted them above Forest and into the play-off reckoning.
Rhodes slotted home precisely from close range for his first, before adding an emphatic header and a superb overhead kick as the visitors ran riot.
"We knew Forest would be a dangerous side, but our game plan was near enough perfection, in terms of our defensive shape.
"We got into good positions and when we did we were ruthless," said Monk. "We did exactly what we needed to do, it was a strong, strong performance.
"We controlled the game from start to finish, it was a fantastic performance and a strong end to the week. We have had a strong week, when you look at two tough away games at Brentford and Forest."
