Match ends, MK Dons 1, Derby County 3.
Two late Derby goals from Darren Bent and Tom Ince condemned MK Dons to their fifth straight league defeat.
Substitute Bent tapped home Ince's cross in the 89th minute before Ince ran clear deep in stoppage time and thumped the ball home.
After a goalless first half, Bradley Johnson put Derby ahead with a sweet low strike into the bottom corner.
Josh Murphy equalised for Dons on the hour mark after some hesitant defending, before the dramatic finish.
It was a cruel defeat for the hosts, who dominated long periods of a pulsating second half and had 26 shots in total.
A quieter first half saw the best chance fall to Dons forward Simon Church, but his volley was saved at point-blank range by Scott Carson.
Eight minutes after the break, Derby went in front against the run of play as former Norwich midfielder Johnson picked up the ball on the edge of the box and placed a left-footed shot past David Martin.
Following Murphy's clinical strike to make it 1-1, Dons pushed forward in search of a winner and Derby were again indebted to former England goalkeeper Carson when he pushed Dean Lewington's header onto the post.
As the game flowed from end to end, Johnny Russell almost put the Rams back in front, but his fierce 30-yard strike hit the crossbar.
Then, in the final minute of normal time, Derby's Jeff Hendrick threaded a wonderful pass through to Ince, who squared the ball for Bent to poke home the easiest of goals.
There was still time for more drama as Carson almost punched the ball into his own net, but Andreas Weimann cleared off the line, before Ince stole the ball off Diego Poyet and sealed the victory.
MK Dons manager Karl Robinson:
"We didn't deserve that at all. For 70 minutes we were tremendous and I always knew that in the last 20 minutes there would be a bit of fatigue because we played on Wednesday night (6-0 defeat by Southampton).
"We were outstanding - we moved the ball efficiently and effectively, which is pleasing to see - but every time they come forward and have a shot it goes in and that's the difficulty for us.
"We have to persevere and we'll start winning football matches. It's easy when you're winning, but when you play the way that we play and you're on a bad run it takes a lot of bravery to play the same way that we do.
"I really do think we've been harshly done by. We've only spent £150,000 on that team out there - but we all work hard here and we're very honest with each other, which perhaps allows us to go on a bad run like this."
Derby boss Paul Clement:
"It's good that Darren Bent's got a goal because I know he's been frustrated. He's not been playing as much as he would like, and to come on and get the winning goal in the 89th minute is very nice for him.
"All of us really wanted to win this game to keep our good run going. It's hard to win any game in this league but we've now won the last three games away from home - and that's not easy.
"We've still got a lot to improve on, but that's a good thing - because if you are picking up positive results and you're not playing that well then I think then we've got a really positive future."
- 7BakerSubstituted forBowditchat 85'minutes
- 10ReevesSubstituted forHallat 79'minutes
- 31MurphyBooked at 70mins
- 11ChurchSubstituted forMaynardat 67'minutes
- 2ChristieBooked at 59mins
- 18ButterfieldBooked at 25minsSubstituted forWeimannat 62'minutes
- 12BairdSubstituted forHendrickat 68'minutes
- 23InceBooked at 77mins
- 9MartinSubstituted forBentat 80'minutes
- Chris Kavanagh
- Shots on Target
Second Half ends, MK Dons 1, Derby County 3.
Goal! MK Dons 1, Derby County 3. Tom Ince (Derby County) left footed shot from the centre of the box to the top right corner.
Corner, MK Dons. Conceded by Bradley Johnson.
Corner, MK Dons. Conceded by Bradley Johnson.
Attempt blocked. Dean Lewington (MK Dons) left footed shot from the left side of the box is blocked. Assisted by Robert Hall.
Kyle McFadzean (MK Dons) wins a free kick in the defensive half.
Foul by Tom Ince (Derby County).
Offside, Derby County. Darren Bent tries a through ball, but Tom Ince is caught offside.
Attempt missed. Kyle McFadzean (MK Dons) header from the centre of the box misses to the right. Assisted by Diego Poyet following a set piece situation.
Dean Bowditch (MK Dons) wins a free kick in the attacking half.
Foul by Bradley Johnson (Derby County).
Offside, Derby County. Bradley Johnson tries a through ball, but Darren Bent is caught offside.
Goal! MK Dons 1, Derby County 2. Darren Bent (Derby County) right footed shot from very close range to the centre of the goal. Assisted by Tom Ince with a through ball.
Foul by Dean Bowditch (MK Dons).
Tom Ince (Derby County) wins a free kick in the attacking half.
Attempt missed. Jake Forster-Caskey (MK Dons) left footed shot from outside the box is too high.
Substitution, MK Dons. Dean Bowditch replaces Carl Baker.
Johnny Russell (Derby County) hits the bar with a left footed shot from outside the box. Assisted by Cyrus Christie.
Corner, Derby County. Conceded by Jake Forster-Caskey.