Chris Wilder launched an astonishing tirade against his "arrogant" Sheffield United players after watching them crash out of the FA Cup with a 1-0 home defeat to non-league Barnet.
Shaquile Coulthirst's first-half penalty saw the Bees eliminate a side 83 places above them in the Football League pyramid at Bramall Lane, and the Vanarama National League side were unfortunate not to win by a bigger margin.
Wilder, who made 10 changes to his side from the team that beat Wigan last time out, accused his players of showing "real arrogance".
"No complaints," Wilder said. "We're quite fortunate that it's not been two or three. They were the better team in every part of the game.
"I said to the boys, 'don't go out through the main entrance, you don't deserve it. Find a door to sneak out of'.
"It was a performance of arrogance, going off plan and doing what they wanted to.
"The fans should have booed the players louder – we've got an identity of playing and we are a team that has a go. We went out the back door today – that is incredibly difficult for me to take."
Wilder is close to signing striker Gary Madine on loan from Cardiff, but admitted he may seek further reinforcements after seeing his fringe players turn in such an underwhelming display.
"That team was good enough to win games of football," he added. "I will take responsibility because they are players that I've signed and hopefully it was a one-off, but I felt there was a real arrogance about the players today.
"This hurts as much as any defeat that I've had in my time.
"I'm not just going to sweep it under the carpet, I'm not going to go along with, 'it's better to be out the cup because of the league position' – that's rubbish.
"I won't be forgetting it. I'm looking at today and thinking that we might not need one, we might need 11 – the players that played today will struggle to be a part of things going forward."
Barnet were unchanged from their draw with Boreham Wood five days ago, and it quickly became apparent that their greater cohesion would cause the hosts problems.
The visitors made a lively start and had already had a goal ruled out for offside when Richard Stearman clumsily brought down Ephron Mason-Clark after a rapid Bees counter-attack, with Coulthirst converting from 12 yards.
Substitute Billy Sharp forced Mark Cousins into his first save of note with a shot on the turn after 68 minutes, before the Barnet keeper acrobatically turned Leon Clarke's header from six yards on to the crossbar in the closing stages.
It was a particularly special occasion for Barnet caretaker boss Darren Currie, whose uncle Tony has a stand named after him at Bramall Lane after a glittering eight-year spell with the Blades from 1968-76.
"I'm so proud, honoured to be leading them the way they performed," said Currie, who confirmed he is keen to take the job on a permanent basis.
"I asked them to play with no fear today and I think they manged to achieve that. They were outstanding."
Asked what his uncle had made of the result, Currie added: "He's proud of me and he felt that we deserved it, that we played very well on the day.
"Naturally he'll be hurting, he wants his team to go through, but he's proud of me and what I've done today.
"It's a job I want, it's the place I want to start. Hopefully today will help me."