MK Dons wasted chance after chance to put Doncaster Rovers to bed and paid the ultimate price, going down 2-1 and four points from League 1 safety.
Ike Ugbo netted the opener after 20 minutes in a half Dons were well on top of. Peter Pawlett had two chances early on, while Ugbo could have doubled his tally five minutes after his first.
After seldom threatening in the opening 45 minutes, Rovers drew level three minutes after the restart when John Marquis tapped in, but while Pawlett, Ugbo and Chuks Aneke all forced saves from Marko Marosi, Marquis' second of the afternoon was too much for the home side to handle.
Dons now need something miraculous to remain in League 1 net season, four points from safety with four games, three of them away, remaining.
MK Dons made three changes from the side which was hammered at by Wigan seven days earlier, with the key being the absence of Lee Nicholls in goal. Wieger Siestma, who hadn't played since the 4-0 defeat to Chelsea U21s back in December. Scott Wootton and Ike Ugbo also came into the side, while Marcus Tavernier and Josh Tymon were on the bench after missing most of Dan Micciche's tenure.
While Sietsma keeper everyone was watching, Rovers keeper Marko Marosi was the busier of the two in the opening 20 minutes. Twice he had to be wise to Peter Pawlett, whose quick feet bought him some space in the penalty area to get a couple of shots off.
Making his first start since March 3, Ike Ugbo wasn't really a part of the game until he opened the scoring on 20 minutes. George Williams and Chuks Aneke combined for the striker to slip in Ugbo behind the Rovers defence, and he coolly fired past Marosi for his second goal in Dons colours.
He could had a second eight minutes later when he once again combined with Aneke to get a shot away, this time deftly lobbing the on-rushing Marosi only to see his effort cleared away from inside the six yard box by Joe Wright.
While Rovers did relatively little the threaten Sietsma's goal, the warning signs were there when Elliott Ward's attempt at a clearance flew up into the air with a Rovers player underneath it.
Fortunately for Ward though, it was centre back Mathieu Baudry, who watched it perfectly onto his laces but sent it sailing over the bar.
First half substitute Alfie Beestin, who replaced Matty Blair early on, also had a great opportunity to bring Rovers level shortly before the interval though he too fired over the top, failing to test Sietsma.
It would take Rovers just three second half minutes to equalise though. Alex Kiwomya's run down the right allowed him to blast a cross into the danger area, but despite Siestma getting a palm to it, John Marquis was on hand to tap into the unguarded net.
It was an end-to-end battle after that. Aneke tested Marosi again from close range, but after Pawlett saw yet another shot denied by the Rovers keeper, the visitors went straight up the other end where Beestin saw his effort come back off the post, with Sietsma beaten.
If Ugbo thought he should have had two already, he certainly was left kicking himself just before the hour mark when, after being picked out by George Williams' low ball into the box, the striker took a touch to settle himself rather than hitting it first time, allowing Ben Whiteman the chance to get his body in the way of Ugbo's eventual effort.
With the number of chances going begging, it was almost inevitable that Doncaster would take the lead and they did so when Marquis got on the end of Tommy Rowe's cross on the edge of the box, lashing the ball past Sietsma on 63 minutes.
Micciche threw on Brandon Thomas-Asante, Robbie Muirhead and Marcus Tavernier in a bid to get back on level terms, and the latter felt he should have been awarded a penalty when Muirhead's ball skipped past Aneke to set the Middlesbrough winger clean through, but despite the close attentions of Baudry, no spot kick was given.
For all Dons huff and puff, Marosi kept his powder relatively dry in the closing stages, and as other results began to turn, Dons' season was left in tatters.
Referee: Nick Kinseley
MK Dons: Sietsma, Lewington (Thomas-Asante 63), Ward, Wootton, Golbourne, Williams, Upson, Brittain (Muirhead 71), Pawlett, Aneke, Ugbo (Tavernier 79)
Subs not used: Jones, Cisse, Agard, Tymon
Doncaster Rovers: Marosi, McCullough (Whiteman 46), Baudry, Mason, Marquis, Rowe, Wright (Butler 74), Houghton, Blair (Beestin 25), Kiwomya, Coppinger
Subs not used: Lawlor, Kongolo, May, Boyle
Booked: McCullough, Pawlett, Brittain, Marquis, Marosi, Houghton, Upson