Blackwell disappointed with Sheffield United's loss
The Blades boss refused to blame the club's growing injury list for the loss, preferring to be realistic about the performance.
"It would be too easy for me to hide behind the fact we have had a load of injuries," he said.
"Today we got what we deserved, which was nothing. We were poor from start to finish.
"We have had 10 injuries and I have got a squad of 22. We couldn't fill the bench. But (to use it as an excuse) would disrespect Scunthorpe, who were at it and deserved the win."