Frank Lampard felt his side could have taken all three points from their game at home to Middlesbrough on New Year's Day.
Harry Wilson gave the Rams the lead inside 90 seconds but Boro fought back to level through Jordan Hugill early in the second-half.
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Both sides could have won the game, Derby in particular finishing strongly, leaving Lampard frustrated at both his side's inability to build on a great start but also the manner in which the visitors got level.
He said: "We had a really good first quarter and the lads did exactly what we expect them to do, but then we let them back into the game and that was disappointing.
"We got sloppy with our passing and let them believe they were in a game. The manner of the goal they scored was disappointing too because we'd worked on that pattern of the throw in, then the cross and the header which they use a lot but couldn't stop it.
"We then finished the game really well and had one really good chance through David Nugent, but it wasn't to be."
Lampard added that Harry Wilson went off with a hip injury early in the second-half, saying: "I'm hoping it's not too bad and the fact it's not a muscle injury is a good thing. We'll assess it in the next couple of days to see if he is OK for Saturday."
The Rams now take a break from league action as they host Premier League side Southampton in the FA Cup third round on Saturday. Their next league game will be at Leeds United on Friday, January 11.
Lampard said: "It's still a very tight and there's not much between ourselves and sides like Boro. We have to keep fighting and will do so long and hard. It's been a festive period where we can be proud of the win at Norwich, disappointed with the Sheffield United performance and then again today not to have taken three points.
"There is unlikely to be much activity in the transfer window but we'll see. I'm not sure there is a lot we can do."