Eric Black was unhappy as Rovers dropped two points late on at Pride Park.
It looked good for Rovers when a sensational strike from Jordan Rhodes put the visiting side in front on 35 minutes, but a below par display in the second half allowed Derby to come back into the match and they snatched a deserved equaliser a minute from time through Theo Robinson.
"I've got to be honest I'm really disappointed that we haven't won the game," said Black after the game.
"I thought our first half performance was okay, there were decent signs, there was a decent balance to it, but the second half, after 15 minutes, I thought we dropped into that lull which is very very frustrating.
"I thought that with the players we had on the pitch we should have won the game today and I'm extremely disappointed that we haven't.
"For the first 15 minutes of the second half I thought we were in control and if we had got the second goal at that point then the game would have been harder for them to come into it.
"But as it happens we dropped and dropped, we didn't get to the ball, we didn't retain possession up front and all of a sudden the pressure comes on.
"We tried to change it to get further up but it didn't happen.
"There's a full house, they're willing them forward and we couldn't protect the lead.
"I'm really disappointed, I just felt our second half performance dropped and I'm really unhappy about that."