Mike Williamson lost his first match as MK Dons head coach as Accrington claimed a 1-0 win to move into the League Two play-off spots.
Shaun Whalley struck in the 31st minute to make it three successive league wins for the Reds while it is now nine games without a win for the Dons, who appointed Williamson four days ago after sacking Graham Alexander.
Mohamed Eisa could have given the new Williamson era a dream start after 40 seconds but his effort went narrowly over the bar.
Chances were at a premium with a Joe Pritchard strike pushed away by visiting goalkeeper Craig MacGillivray after 14 minutes.
Stanley took the lead just after the half-hour mark when Pritchard found the unmarked Whalley in the area and he made space for himself before firing the ball into the roof of the net.
Dons top scorer Eisa had another two chances before the break but was unable to find the target.
Whalley came close to a second for the home side after 50 minutes but MacGillivray denied him from close range.
MK Dons pressed for the equaliser with Max Dean coming close but they were unable to avoid defeat and drop to 18th place.
