Aidan Nesbitt's eighth minute strike was enough to secure Dons' first away points of the season against 10-man Plymouth Argyle in a poor display from Robbie Neilson's side.
Lashing home Callum Brittain's cross, Nesbitt made his mark, but after Graham Carey's 33rd minute sending off, the home side were by far the better. Stuck for ideas, lacking in chances and attacking prowess, Dons limped in at the finish at Home Park, somewhat fortunate to come away with the win.
For the longest journey of the season, Robbie Neilson was able to welcome back Osman Sow to his starting 11 for the first time since early August, and he went streight into the starting 11, leading the line at Home Park. And after scoring the equaliser against Oxford United, Callum Brittain was given a start in teh absence of Ethan Ebanks-Landell. Aaron Tshibola missed out through illness.
Having made such an impact after coming on against Oxford, Brittain was in the thick of it again after just nine minutes, teeing up another Dons player Robbie Neilson holds in high regard for the future - Aidan Nesbitt. Brittain's ball into the mix was over Osman Sow and Ed Upson, but found the deadline day signing at the far post to control and lash in at the near post to give Dons the lead.
Brittain was almost the orchestrator again nine minutes later when he lofted a ball over the Plymouth defence for Alex Gilbey to chase, but the former Wigan man fired just wide of the mark.
The Pilgrims' defence looked distinctly average in the opening stages, and yet another ball over the top carved them open, but Gboly Ariyibi just dragged his strike wide after Scott Golbourne's pull back.
But Plymouth's weaknesses at the back were obvious, their attacking prowess looked a lot sharper. While David Fox and Jake Jervis fired efforts over the top, Nadir Ciftci thumped the bar with a brilliant free kick, which would have gotten them back on level terms but it would have been an unjust equaliser as the visitors looked by far the better side.
And they were handed a huge boost with 12 minutes go to when Graham Carey, by far Plymouth's most lively attacking threat, caught Ariyibi high up his shin and was immediately shown the red card to reduce the home side's chances.
But they will have felt they should have gone in level at the interval when Ciftci burst through the Dons defence and went one-on-one with Lee Nicholls, but fired straight at the keeper.
The second half was a far cry from the first though. Far from the ease at which Dons played out the opening 45 minutes, it was a lacklustre and off-colour side that emerged for the second, inviting Plymouth onto them rather than pushing on and looking to punish the side with 10 men.
It allowed Argyle to give themselves a sniff of a point, but Joel Grant missed an absolute sitter from close range, firing sensationally high and wide when scoring looked easier.
Such was the home side's control over the half, Dons didn't even register a shot in the second period. Osman Sow was left isolated all too often in his return to the side, but the midfield simply went missing.
Fortunately for Dons, Plymouth struggled to find the target when they saw sight of goal. Sonny Bradley had to do better when he met Lionel Ainsworth's corner late in the day, but could only glance it wide as Dons held on in unconvincing fashion.
Referee: Charles Breakspear
Attendance: 8566 (211)
Plymouth Argyle: McCormick, Miller (Lameiras 80), Sawyer, Edwards, Ness, Ciftci (Fletcher 69), Carey, Jervis (Ainsworth 69), Bradley, Grant, Fox
Subs not used: Te Loeke, Songo'o, Blissett, Wylde
MK Dons: Nicholls, Brittain, Wootton, Williams, Golbourne, Upson (McGrandles 16) Ariyibi, Nesbitt (Agard 83), Sow (Muirhead 72)
Subs not used: Sietsma, Lewington, Agard, Seager, Thomas-Asante
Booked: Edwards, Grant, Williams, Sow, Muirhead, Cisse, Lameiras
Sent off: Carey