Sheffield United's automatic promotion hopes were dented after Alan Smith's first-half header for MK Dons consigned Danny Wilson's side to defeat.
The result means they are just one point ahead of city rivals Sheffield Wednesday with two games left to play.
Smith headed home from close range to open the scoring while Gary MacKenzie also hit the post for MK Dons.
Jabo Ibehre later fired a shot against the post for the Dons, while Daniel Powell was also sent off for the hosts.
MK Dons remain fourth, level on points with Huddersfield in fifth, with their play-off place already confirmed.
VIEWS FROM THE DRESSING ROOM
Sheffield United manager Danny Wilson told BBC Radio Sheffield:
"We didn't have enough tempo and energy in our play in the first half.
"We created one or two little opportunities, but didn't make the most of it and offered too much possession to MK Dons.
"We had a couple of escapes. They hit the post a couple of times.
"But we're quite frustrated we didn't put the few chances away that we had."
Live Text Commentary
Full Time The referee blows his whistle to end the game.90:00 +3:32
Free kick awarded for an unfair challenge on Michael Doyle by James O'Shea. Michael Doyle takes the free kick.90:00 +2:24
Matthew Hill gives away a free kick for an unfair challenge on Jabo Ibehre. Gary MacKenzie restarts play with the free kick.88:53
Michael Doyle has an effort at goal from just outside the penalty box which goes wide of the left-hand post.86:39
Corner taken left-footed by Shaun Williams from the right by-line, Header from deep inside the area by Gary MacKenzie goes over the bar.85:34
Effort from inside the area by Jabo Ibehre hits the post.83:50
Lee Williamson takes the outswinging corner, clearance by Jabo Ibehre.82:24
Free kick awarded for a foul by James Beattie on Darren Potter. Darren Potter restarts play with the free kick.81:56
Jabo Ibehre takes a shot from 18 yards. Steve Simonsen makes a save.75:59 Substitution
Substitution James Beattie comes on in place of Chris Porter.73:51 Substitution
Substitution James O'Shea comes on in place of Dean Bowditch.70:29
Corner from the right by-line taken by Lee Williamson, save by David Martin.68:26 Substitution
Substitution Jabo Ibehre is brought on as a substitute for Alan Smith.67:59 Substitution
Substitution Luke Chadwick comes on in place of Charlie MacDonald.66:08 Dismissal
Dismissal Daniel Powell shown a red card for second bookable offence.65:29
Daniel Powell concedes a free kick for a foul on Matthew Hill. Free kick taken by Matthew Hill.64:26
Corner taken by Shaun Williams from the right by-line, Lee Williamson makes a clearance.61:03
Inswinging corner taken by Shaun Williams from the right by-line, Dean Bowditch takes a inswinging corner to the near post, Alan Smith takes a shot. Clearance made by Matthew Hill. Harry Maguire manages to make a clearance.60:42
Header from inside the area by Gary MacKenzie strikes the post.59:24 Substitution
Substitution Ryan Flynn replaces Stephen Quinn.
Substitution Will Hoskins leaves the field to be replaced by Michael O'Halloran.59:24
Unfair challenge on Stephen Gleeson by Lee Williamson results in a free kick. Direct free kick taken by Dean Lewington.54:15
Dean Lewington fouled by Lee Williamson, the ref awards a free kick. Free kick taken by Dean Lewington.52:04 Booking
Booking Booking for Daniel Powell for unsporting behaviour.49:17 Booking
Booking Stephen Gleeson receives a caution.49:03
Free kick awarded for an unfair challenge on Matthew Hill by Stephen Gleeson. Indirect free kick taken by Neill Collins.45:01
The game restarts for the second half.45:01 Booking
Booking David Martin is cautioned by the ref for time wasting.45:00 +2:09 Half time
Half Time The referee calls an end to the first half.45:00 +1:52
The assistant referee flags for offside against Alan Smith. Neill Collins takes the direct free kick.45:00 +0:52
Corner taken left-footed by Shaun Williams from the right by-line, Neill Collins makes a clearance.44:18
Outswinging corner taken by Lee Williamson, save made by David Martin.41:30
Free kick awarded for a foul by Adam Chicksen on Chris Porter. Indirect free kick taken by Matthew Hill.40:32 Booking
Booking Dean Lewington is booked.40:26
Unfair challenge on Dean Lewington by Lee Williamson results in a free kick. Dean Bowditch takes the direct free kick.40:04 Booking
Booking Lee Williamson is shown a yellow card for unsporting behaviour.37:48
Handball by Dean Lewington. Matthew Lowton takes the indirect free kick.35:20
The assistant referee flags for offside against Chris Porter. Shaun Williams takes the free kick.34:10
Lee Williamson gives away a free kick for an unfair challenge on Alan Smith. Stephen Gleeson takes the direct free kick.33:02
Dean Bowditch has an effort at goal from just outside the box which goes wide of the left-hand post.31:59 Booking
Booking Stephen Quinn is given a yellow card.31:19
Stephen Quinn challenges Adam Chicksen unfairly and gives away a free kick. Adam Chicksen takes the direct free kick.27:02
Chris Porter produces a left-footed shot from just outside the area that goes harmlessly over the bar.22:28
Free kick awarded for an unfair challenge on Adam Chicksen by Stephen Quinn. Darren Potter takes the direct free kick.21:50
Free kick awarded for a foul by Will Hoskins on Charlie MacDonald. David Martin takes the indirect free kick.21:08
Outswinging corner taken by Lee Williamson from the right by-line played to the near post, clearance by Alan Smith.18:48
Handball decision goes against Chris Porter. Indirect free kick taken by David Martin.15:21
Assist by Daniel Powell.15:21 Goal scored
Goal! - Alan Smith - MK Dons 1 - 0 Sheff Utd Alan Smith scores a headed goal from close range. Milton Keynes Dons 1-0 Sheff Utd.14:52
Corner from the left by-line taken by Dean Bowditch,14:20
Corner taken by Shaun Williams from the right by-line, Chris Porter manages to make a clearance.6:21
Inswinging corner taken from the right by-line by Shaun Williams, clearance made by Chris Porter.3:25
Free kick awarded for a foul by Alan Smith on Kevin McDonald. Harry Maguire takes the indirect free kick.2:33
Free kick awarded for an unfair challenge on Dean Bowditch by Lee Williamson. Direct free kick taken by Darren Potter.1:16
Foul by Stephen Gleeson on Matthew Lowton, free kick awarded. Steve Simonsen takes the indirect free kick.0:00
The referee starts the match.
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