Three second-half goals saw the Dons record another impressive away-day victory and move to within three points of second place.
Dean Lewington was fit to start, while Jordan Spence, Rob Hall and Lewis Baker came in too. Joe Walsh (knee), Lee Hodson, Dean Bowditch (personal reasons) and Samir Carruthers (suspended) made way.
The Dons began on the front-foot and Hall forced Chris Maxwell into a save as early as the first minute from 20 yards following good build-up play between Will Grigg and Dele Alli.
Karl Robinson’s men maintained their strong start with Alli seeing an effort on the edge of the Fleetwood box after another spell of good possession.
Kyle McFadzean comfortably dealt with a cross from the right, which was the catalyst for another Dons move – Lewis Baker firing over at the end of it from 25 yards.
David Martin watched Ashley Hunter’s long-range shot past the post on 15 minutes before the debutant striker saw an acrobatic effort brilliantly blocked by McFadzean.
Trying to also make an impression at the other end, centre-back McFadzean forced Maxwell into a superb fingertip save from 25 yards – nothing came from the resulting corner.
With the Dons sensing an opener, Lewis Baker let fly from a similar distance with his stunning effort coming crashing back off the crossbar midway through the first half.
Alli was presented with a golden chance to break the deadlock on 27 minutes but he shot into the ground and it looped over the bar from 10 yards.
Like Fleetwood earlier, the Dons were lucky to be level on the half-hour mark when Gareth Evans, who started the slick attack for the home side, fired against the bar from in line with the penalty spot.
Hall, who was looking lively down the right, shot down the throat of Maxwell before sending a drive narrowly wide of the post in quick succession in the 33rd minute.
Grigg came very close to his 20th goal of the season five minutes before the break when he received a clever pass from Lewington and slid his effort inches off target.
This was closely followed by Alli volleying Powell’s cross wide as the Dons kept up the heat on the hosts until the half-time whistle.
Fleetwood began the second half the better of the two teams and the dangerous Evans blasted over following good work down the right by Antoni Sarcevic.
But it was the Dons who went ahead on 55 minutes when Hall played in Alli and he crossed for Lewis Baker, who made no mistake with a smart finish from close range. 0-1
That provided the men from MK1 with a platform to build on and almost did immediately with Alli and Grigg both forcing saves from Maxwell in quick succession.
It was ever so close to being 2-0 on 61 minutes when Antony Kay’s effort on the turn was palmed away by Maxwell and then Alli’s rebound skimmed the post.
Buoyed by his goal, Lewis Baker went in search of a second and his stunning curling 25-yard effort almost doubled the Dons’ advantage shortly afterwards.
At the other end, Martin, who had been a spectator for most of the evening, was alert to push Morris’ deflected shot away from danger.
Grigg extended the lead on 74 minutes when he outmuscled and won the ball of Stephen Jordan, pushed it past Nathan Pond and then coolly slotted home for his 20th goal of the season. 0-2
Alli all but secured the success with a sensational strike on the half volley four minutes later after the ball had dropped to the 19-year-old wonderkid 20 yards out. 0-3
Spence almost got in on the act with eight minutes remaining but his fierce 25-yard drive was expertly tipped over by Maxwell.
MK Dons: Martin; Spence, Kay, McFadzean, Lewington (c); Potter, Alli; Hall (Cole 75), L Baker, Powell (Green 84); Grigg (Hitchcock 78).
Unused subs: Burns, Hodson, Flanagan, C Baker.
Bookings: Lewington, Alli.
Goals: Baker (55), Grigg (74), Alli (76).
Attendance: 2,752 (186 Dons fans).