After conceding a penalty to go behind in the first-half, a Warren Kayembe strike on 74 minutes looked to have earned 'Side a well-derserved point.
However a Moses Carvelio shot four minutes from time, struck a bobble in the pitch. This cruelly deceived Mikel Breckenridge in goal to give Stansted the victory.
The result leaves 'Side five points off 19th placed Tower Hamlets.
Michael Walther's men are back in action on Wednesday night when they face Walthamstow away from home. Kick-off at Wadham Lodge for that match is at 7:45pm.