Rotherham assistant manager Paul Raynor slammed his side's defending as they lost 3-2 to Rochdale, their first home loss.
The visitors grabbed the lead at the end of the first half through Dele Adebola, but Rotherham equalised thanks to an Alex Revell bullet header.
The Millers took the lead soon after through Daniel Nardiello but a Bobby Grant penalty levelled things up again before Kevin McIntyre fired in the winner with 10 minutes to go.
Raynor, standing in again for banned boss Steve Evans, said: "The first half was very disappointed, but at half-time we shook it up, got a grip and went ahead, and I felt we deserved to do so.
"We were on the front foot, but then a bit of suicidal defending, when we gave away a free-kick on the edge of the box, lets them in. We defended the free-kick and the corner and then Alex Revell dangled a leg and they get a penalty.
"When you are 2-1 up you cannot defend like that. You cannot concede three goals at home that is for sure. We thought we had eradicated that, but they were down to individual errors."