Grant McCann said he did not recognise his Doncaster Rovers side in the second half as they let a lead slip at Scunthorpe United.
Rovers were in a position of command at half time despite only leading through Mallik Wilks' strike.
But their performance levels dropped after the break and Scunthorpe earned a deserved equaliser through Kyle Wootton, much to the frustration of boss McCann.
"I just felt really disappointed," McCann said.
"I didn't recognise my team in the second half.
"They didn't move the ball quick enough, we didn't create enough chances and when we did create chances we were slashing at them.
"We could have put the game to bed at 2-0.
"We just invited pressure onto ourselves, we didn't get the press right and we were sitting off them.
"When you play a side like Scunthorpe, they want you to sit off them so they can hit massive diags to Lee Novak and Kyle Wootton.
McCann was disappointed with the manner in which his side allowed Scunthorpe into the game in the second half - something he felt was typified by the goal.
Tony McMahon was afforded plenty of space on the right to send a cross to the back post where Wootton charged in to head home.
McCann said: "For how good we were in the first half, we were poor in the second.
"We played into their game plan, we played into the way they wanted us to play.
"We knew what was coming.
"Their game was to hit big massive diagonals to Wootton, and try to compete against Matty Blair.
"Or to put crosses into the back post for Wootton at the back post.
"We spoke about this before the game and at half.
"We didn't stop the cross and we didn't defend the back post. It was as simple as that.
"The first half we were excellent.
"The second half we were bang, bang average."
On the reasons for the dip in performance, McCann felt Rovers' composure escaped them in the second half and insisted he had no argument with the final results.
He said: "I thought we lacked composure.
"First half we were good but we just weren't clinical enough. We should have come in two or three up.
"In the second half Scunthorpe were better than us and deserved a goal.
"We couldn't press them or get about them enough.
"We looked like we had a lack of energy in the team in the second half, which surprised me really."