Josh Gowling scored a late winner for Kidderminster to leave Nuneaton six points off safety in the Blue Square Bet Premier.
Callum Gittings had a shot blocked by Gavin Cowan and Anthony Malbon forced two saves from Adam Smith as Harriers started the brighter.
Adam Walker had a chance for Boro before Gowling headed home Lee Vaughan's cross after 89 minutes.
Harriers are now two points above the relegation places.
VIEW FROM THE DRESSING ROOM
Kidderminster manager Steve Burr told BBC Hereford & Worcester:
"Sometimes you don't get what you deserve but we thoroughly deserved that victory. If we hadn't have won I'd be very disappointed.
"It was just about keeping patient. It was nice to see the set-piece corner that we work on in training and for Josh Gowling to get on the end of it was great.
"They made it very hard to break them down but we had to keep a good tempo and got our rewards."