Derby head coach Paul Warne reckoned his team cost him “three weeks off his life” after it took a stoppage-time winner to beat Burton.
Warne saw his players throw away a two-goal lead, only for skipper Conor Hourihane to score deep into added time.
Derby looked to be cruising to victory when Tom Barkhuizen scored at the back post in the 29th minute and James Collins headed a second four minutes after the break.
But Burton hit back in the 54th minute through Steve Seddon, who drove a low 20-yard shot past Josh Vickers.
The visitors were level 11 minutes later when Manchester United’s on-loan striker Joe Hugill broke away to score on his Burton debut.
But Albion’s brave resistance was broken in the third minute of stoppage time as Hourihane found the bottom corner from the edge of the area.
Warne said:” I thought we were good for 50 minutes and then we had a wobble. We were on a roller-coaster a little bit and that’s what disappointed me a bit about the performance.
“I thought we lost a bit of our character, we’d gone from complete control, although fair play to Burton, they made it really difficult for us.
“So for the captain to score late on was great and if nothing else it was entertaining for the neutrals, but I’ve lost at least three weeks off my life with that!
“Hopefully next time if we go 2-0 up we’ll have a little bit more control and keep trying to do the right things because tonight I felt we got away with it.
“We need to be better, if you want to go up and you want to win you have to be good in all the moments in most of the games.”
Burton manager Martin Paterson said: “The boys are disappointed, so am I. I’ve said many times to them in my first couple of days it’s a results-based business, we are here to win games and get points.
“So when we don’t we have to be disappointed. I’ve told them results are on me, that’s my job, their job is performance, so when you lose like that emotional control is key for me.
“You feel terrible, but the positives you take from it are it’s Derby, it’s a packed house and they are absolutely delighted. You saw how they celebrated a last-minute goal and my group have pushed them to the point where it’s euphoria.
“No disrespect to a really good football club, the manager’s good, the players are good, but there’s a little bit in me that thinks second half probably wasn’t a fair result.”