The 3-0 home defeat to Gateshead was “nowhere near good enough” for the experienced manager.
Their winless run now stands at nine - and this home hammering was defeat number seven in that horror run.
On Friday the former Barnet and Leicester City manager said he expected his team to be challenging for the title at this stage.
But they are now just a point outside the bottom four after waving the white flag to the Heed.
Allen said sorry to the supporters and vowed they wouldn’t see anything like that again.
“It’s a total let down for all our supporters,” said Allen to the Derbyshire Times. “I feel let down.
“I’m very, very sorry to all our supporters who came to watch that.
“I’ve said so far this season we’ve played well, at times we’ve been unlucky, not got what we deserved - today was the complete opposite of that.
“That was as bad as I’ve seen a team of mine play. We lacked energy, enthusiasm, pace, power, tenacity.”
He added: “I’ve been doing this now for over 500 games, I think that today was going to rank up there as the worst I’ve seen.
“It was embarrassing. I’m hurt, really.”