Alex Neil' s side had briefly looked like turning their ailing form around when Ross Stewart scored a superb header to level the scores midway through the second half, but the Black Cats had been vulnerable to the counterattack throughout and were punished with fifteen minutes to play.
They had struggled throughout to carve out significant chances, the gameplan of the visitors working comfortably as they soaked up limited pressure and broke in numbers when the opportunity allowed.
The result means that the Black Cats have now dropped out of the play-off places.
Neil opted to make only minor changes to the side who had laboured at AFC Wimbledon in his first game in charge, Carl Winchester dropping back into defence and Corry Evans returning as the midfield anchor.
The visitors came into the game two points and one place ahead of Sunderland in the table and from the off it was clear they they would be content to sit in and frustrate the hosts.
They defended dip and in number, opting not to press the home side in a bid to cause frustration. When they did win it back they played it forward and quickly, and caused some problems in a clearly uncertain defence trying to play a relatively high line.
Neil had kept faith with Anthony Patterson despite the return of Thorben Hoffmann, and he justified his selection with some good work in the first half.
He was alert to a ball over the top eight minutes, rushing off his line to block the effort from wing-back Tennai Watson. Minutes later he made another good stop when Mo Eisa, whose runs off the shoulder were causing problems, was allowed to twist away from his marker in the box.
MK Dons may well have been encouraged by those openings but in truth they did little to really build on it.
Manning’s side took time out of the game at every opportunity, taking time over every throw in and free kick. It was in truth a dire spectacle, Sunderland lacking the confidence and the tempo to open their opponents up.
For the second game in a row, Pritchard looked wasted on the wing and Stewart isolated the middle.
Their only opening of the half came when a corner was whipped into the middle of the box by Pritchard, headed wide by Stewart who was adamant that the final touch came fro his marker Harry Darling.
Just before that the visitors had forged the best chance of the half, a quick free kick over the top of the defence allowing Parrott to shoot on goal. Patterson did well again, palming the effort over the crossbar.
It had been an insipid first half, with much to ponder for Neil.
There was some welcome urgency at the start of the second and almost an opening goal, Stewart making a good run into the right-hand channel and firing in a low cross that just evaded Pritchard.
The optimism lasted a matter of moments, the breakaway goal that the visitors had threatened to produce throughout the first half coming within moments.
Sunderland were adamant that Matete was fouled as he was caught in possession, but the referee waved play on and from the home side were too slow to react. Eisa was sprung clear and this time there was nothing Patterson can do as a low and firm effort flew past him and into the far corner.
The Black Cats should have equalised immediately afterwards, but when a free kick fell for Dajaku inside the box he could only blaze wide on his weaker right foot.
Neil turned quickly to his bench, and the changes paid immediate dividends. The referee finally called the visitors out on their timewasting antics, waving play on as McEachran feigned injury just inside his own half. Sunderland took a free kick quickly, and with his first touch of the game Embleton unfurled a glorious inswinging cross onto the head of Stewart, whose deft effort left Cumming with no chance.
The Stadium of Light erupted, with half an hour still to play.
The changes had got the hosts on the front foot, and they were on top as Stewart just failed to control a Clarke cross before Matete fired wide from range.
Perhaps inevitably, they fell behind again as Whickham scored with his first significant action.
Evans was caught in possession on the halfway line, and the visitors broke quickly. Parrott did well to keep his composure and play in his team-mate, who shifted the ball on to his left foot with his first touch and fired past Patterson with his second.
It had been a good spell for the hosts, but the wind had visibly been taken out of their sails.
Sunderland did rally slightly towards the end, with Stewart heading over from a good Pritchard free kick, but Cumming had rarely neen tested throughout and overall, it was another in which the Black Cats did not do anywhere enough to win.
Sunderland XI: Patterson, Winchester, Wright, Doyle, Cirkin; Evans (Roberts, 77), Neil (Clarke, 55), Matete; Dajaku (Embleton, 55), Pritchard, Stewart
Subs: Hume, Xhemajli, Hoffmann, Defoe
MK Dons XI: Cumming, Watson (Kesler Hayden, 87), Lewington, O’Hora, Darling, Twine, Eisa (Wickham, 72), Coventry, McEachran (Kasumu, 61), Parrott, Harvie
Subs: Ravizzolli, Smith, Boateng
Bookings: Evans, 24 McEachran, 24