A late goal from forward Callum Ball proved not enough as goals either side of the interval for the hosts did the damage.
Boosted by the announcement of Maamria as manager ahead of kick off, Boro began brightly in the pouring Manchester rain.
Jordan Nicholson diverted a Daniel Nti effort goal bound, only to be denied by sharp reflexes from Lloyd Allinson in the FC United goal.
Frontman Ashley Chambers continually probed the home sides defence, whilst Greg Mills saw a fizzing effort turned away. Nti was next to try his luck, only to be denied by a sharp save when through on goal.
However with just over 30 minutes on the clock FC United, who had earlier had a goal ruled out for offside, opened the scoring.
Craig Lindfield's floated free kick was misjudged, allowing for Jason Gilchrist to prod home, giving the hosts a first half lead.
This could have been added to moments later, but Dean Lyness got down well to both stop and hold Tom Greaves low skidding effort.
After the interval the visiting Boro troops again went on the offensive, with both Mills and Chambers denied in quick succession by Allinson in the FC United goal.
But as with the first 45 minutes Boro were made to pay as on the hour mark the home side doubled their lead.
Another free kick from Lindfield caused confusion and it was Jordan Fagbola who profited, stabbing home from close range.
Yet despite the setback Boro continued to press. Nicholson fired just wide, before a breakthrough was made.
Second half substitute Callum Ball reacted quickest as a Nicholson effort was spilt, allowing the introduced frontman to slot home from close range for his first league goal of the season.
Looking to take a point from a high intensity encounter Chambers attempted a long range chip that went just over, before both Nicholson and full back Luke Trotman saw efforts edge just the wrong side of the woodwork as time ran out on the Boro.
Updated 20:35 - 28 Oct 2017 by OL 2