Derby County boss Gary Rowett described his team's performance as the 'worst he has ever had to sit and watch' as a manager.
Rowett's side came into the game with the chance to capitalise on some poor results for teams around them in the play-off hunt, but could only watch on in horror as the fell to a 4-1 defeat.
The Black Cats missed a glut of opportunities to give the scoreline an even more emphatic look, and Rowett could not hide his disdain for what he saw from his defence.
He said: "It's a difficult night to stand on the sideline and feel any positives at all. In six years of management it is probably the worst 90 minutes I've ever had to sit and watch.
"The most disappointing bit for me is that, I'm not in any way going to discredit to Sunderland who are fighting for their lives, but all four goals were self-inflicted.
"As a manager that is very difficult to take," he added.
"I'll be the first one to question if my tactics are right, if I got my team wrong, but it is difficult to say that when all the goals come from our mistakes.
"The third goal was a really pivotal one.
"I can't keep eulogising about the players, someone told me we're still in the top six, I don't know how.
"I'm going to have to have a look and see which players I think can do it when there pressure is on, because in any run-in it is all about how you handle the pressure.
"You need to play the same game as when the pressure isn't on. Tonight we didn't do that."
The 44-year-old said he was 'embarrassed' and would not take the blame for his team's shortcomings.
He said: "I'm not even really angry, I'm just a tad embarrassed, because I've not seen many of my teams play like that in the past.
"At the same time, as the manager, I've got to very quickly decipher what to do ahead of a game on Monday. The first thing is telling like it is, and that's not deflecting away from me."