Stuart McCall expressed his frustration after errors cost his side in a 2-1 defeat at Newport County.
The Bantams took the lead before the half-hour mark, though were undone by two corners - prior to half-time.
McCall hinted there were no excuses for the goals his side gave away and was disappointed by the nature of the loss.
He said: “It is hugely frustrating. We can say what we want afterwards, in the dressing room, but we knew exactly what to expect - coming into the game.
“We knew set pieces would prove dangerous for them and they have had three corners and scored from two of them.
“When you come to a place like Newport - where they have not won in a while and are struggling with confidence - you need to get together as a unit and remain solid when you go 1-0 up.
“We switched off and lost two goals from really were not two great set-plays.
“There was a big lack of responsibility. Where we should have pinned them down in the first half and pushed for another goal, we let them back into it, which is disappointing.”
McCall insisted defeat was not for the want of desire from his players, and was mainly pleased with their application.
He admitted this makes the result hurt all the more and his side must quickly bounce back.
The City chief added: “I thought we could have still gone on and won it, in the end.
“We probably deserved a goal in the second half, but we will never win matches if we cannot defend set-plays properly - and that cost us.
“On the bright side, we did create opportunities and should have scored two or three goals.
“Football is massively about how well you do in both penalty areas, and errors let us down.
“Losing should never be acceptable and it does not go away easily, but we have to take it on the chin.
“There was not a lack of desire, it was the intelligent side of the game which saw us lose.”
McCall’s men return home to the Utilita Energy Stadium next Saturday (February 29), hosting Plymouth Argyle. CLICK HERE to purchase tickets.