Carl Baker’s second-half strike saw the Dons run out 1-0 winners over Sheffield United and keep up the pace with the top two in League 1.
Baker coolly slotted home from 20 yards from Grigg's lay-off, as the men from MK1 opened up a 12-point advantage on Bradford City, who occupy the final play-off spot.
Karl Robinson was forced into one change with Dean Bowditch coming in for Darren Potter, who was absent due to personal reasons.
After an evenly-contested opening, the first chance of the game fell to Samir Carruthers, who saw his 20-yard shot deflect into the grateful arms of Mark Howard.
In the 15th minute, a fantastic bit of skill and then a clever pass from Carl Baker found Bowditch, who gave the ball back to the winger but, after cleverly getting away from his man, he fired into the side-netting from 15 yards.
A mix-up between Howard and Jay McEveley almost presented Dele Alli with a chance midway through a half the Dons were beginning to control, but the midfielder couldn’t quite get around the defender before the keeper claimed.
Alli was at the heart of a slick move involving three Dons a minute later but the former couldn’t quite find a team-mate when he got to the byline.
Michael Doyle fired a warning shot for the Blades when he sent an effort wide of the target from 25 yards as the clock ticked towards the half-hour mark.
After a perfect cross-field ball from Alli, nice link-up play between Jordan Spence and Ben Reeves won the Dons a corner shortly afterwards, however, nothing came of the resulting set-piece.
Some more intricate build-up created a chance, albeit a very difficult one, for Bowditch, and his flicked header from Reeves’ cross was easily caught by Howard.
Baker flashed a 25-yard effort not too far over the top on 38 minutes while, at the other end, Terry Kennedy couldn’t get enough on Jose Baxter’s dangerous free-kick and David Martin gathered.
The lively Baker forced Howard into a smart save down to his right, again from distance, on 41 minutes, but the best chance in the dying embers of the first period fell to Jamal Campbell-Ryce, who was brilliantly denied by Martin when put through one-on-one.
Spence stung the palms of Howard with a rasping 20-yard effort two minutes into the second half as the Dons looked to turn their pressure into an opener.
At the other end, Blades substitute Louis Reed sent a shot just past the left-hand post on 52 minutes which lifted the visitors.
Robinson tried to bring a fresh spark to his side’s attack by introducing new signing Jonson Clarke-Harris in place of Bowditch with 25 minutes remaining.
However, it was one of the starters who made the breakthrough two minutes later – Baker coolly slotting into the bottom right-hand corner from 20 yards after Will Grigg had made a nuisance of himself.
Looking sharp, Clarke-Harris latched on to Alli’s through-ball and fired into the side-netting on 70 minutes as the men from MK1 chased a quick second.
The Blades were almost level, though, on 75 minutes when Campbell-Ryce’s teasing delivery fizzed all the way across the six-yard box.
Substitute Che Adams shot straight down the throat of Martin from a 20-yard free-kick while, at the other, Antony Kay saw a goal-bound effort blocked with five minutes remaining after the Blades had failed to clear a free-kick.
The two Michaels – Higdon and Doyle – sent efforts wide of the target in the final minutes but, in truth, the Dons saw out the game fairly comfortably.
Starting XI: Martin; Spence, Kay, McFadzean, Lewington; Carruthers (Randall 86), Alli; Reeves (Baldock 90), Bowditch (Clarke-Harris 65), Baker; Grigg.
Unused subs: McLoughlin, Hodson, Green, Hitchcock.
Bookings: McFadzean, Spence, Baker.
Goals: Baker (67).
Attendance: 9,633 (1,451 away)