Tony Mowbray turned his ire on the officials as Derby denied Middlesbrough the chance to climb to eighth in the Championship table.
Lucas Jutkiewicz looked to have earned a fourth home league win of the season for the hosts as he completed his brace five minutes from time.
But Paul Coutts benefited from a spot of pinball in the Boro box to end Derby's losing streak at the Riverside, after Theo Robinson had put Nigel Clough's men ahead from the penalty spot in the first half.
For the second time in a week, Mowbray was left to rue a late goal.
He had not argued with the legitimacy of Nathan Dyer's winner for Leicester on Saturday, but was convinced a Derby player had been offside in the build-up to Coutts' scrambled goal on Wednesday night.
"When you get yourself in front so late on the expectation is that you'll take all three points," the Boro boss said.
"The frustration is that the goal was offside, but we sit here at 2-2 and can't change it now because the officials got it wrong.
"It's frustrating when they do but you'd have to say on the balance of play that Derby deserved to take something from the game.
"Derby showed they're a decent team, they've got some nice tidy footballers and counter-attack very well.
"We have to find a way of winning football matches. The first three matches were very, very tight, all decided by the odd goal.
"I think there was evidence tonight that we lacked a bit of creative spark, somebody to beat people and drive past people, but the reality is that those type of players are not available to us at the moment.
"If the officials had done their jobs properly you'd have to say that there wouldn't have been a goal and we'd have won 2-1, but that's football.
"That's the fine margins of football and we have to live by them."
An attendance of just 13,337 represented the lowest-ever turnout for a league game at the Riverside, leading Mowbray to ponder why the fans are staying away.
He added: "The crowd has been low all season, and as I've said since I came here, it's disappointing to look up and see the empty seats. We will see.
"Is it the lack of entertainment, is it financial? I'm not sure it's the fact that we're not winning.
"We've got to look deep into the reasons as to why the fans aren't coming."
His Rams counterpart, though, was cheered to see continuing traces of the fighting spirit that earned Derby a 1-0 victory over fierce rivals Nottingham Forest at the weekend.
Clough said: "On the back of the effort that went in on Sunday, to come back from 2-1 down with minutes to go means the spirit and honesty of these lads is not in question.
"We have certain principles when we score a goal, we have to get the ball back and not give it away for a few minutes but we didn't do that.
"There were two or three mistakes leading up to (Boro's equaliser), Jeff Hendrick giving the ball away on the halfway line then conceding the free-kick before Frank (Fielding) spilled it.
"If we'd stopped any one of those then the ball wouldn't have gone in.
"And I don't think it would have been undeserved if we'd gone away with a 3-2 win."
