Elliott Durrell scored a second successive deflected goal as Wrexham broke the resistance of Kidderminster late on.
The buzzing midfielder, buoyant after getting off the mark in Saturday's convincing 3-0 triumph over Eastleigh, fired the decisive goal six minutes from time in a match that looked to be goalless from the opening stages.
Wrexham probed for an initial opening but a Mark Carrington volley on the turn in the eighth minute was just about as good as it got.
Indeed, it was a pretty dire first half, devoid of chances, which merely served to undermine the quality of two sides expected to be in and around the playoffs come March next year.
Reds fans had to wait until the hour mark before they could afford to rise off their seats in anticipation, but Louis Moult fired wide of goal after Harriers keeper Danny Lewis spilled under pressure from Connor Jennings.
Dan Bachmann then showed cat-like agility to beat away a low Michael Gash drive as the visitors gained momentum.
However, it was the hosts who finally edged ahead, Durrell's shot deflected into the net after taking Andy Bishop's pass in his stride.
Jennings had started the move with a ball out wide to Ashton on the left and his cross field pass had found Clarke on the the right side for the Kidderminster box, In turn the midfielder stabbed the ball to Bishop, so eight yards from goal, but with is back tot he target he laid a pass back to Durrell, who fired goalwards at the first attempt and it took a touch off Jared Hodgkiss to divert passed keeper Lewis.
Harriers failed to react and Wrexham clung on to the very epitome of an ugly win, one which did though propell them into the playoff places.
Wrexham: Dan Bachmann, Mark Carrington, Manny Smith, Blaine Hudson, Neil Ashton; Wes York (Andy Bishop 69), Dean Keates, Joe Clarke, Elliott Durrell (Johnny Hunt 89); Louis Moult, Connor Jennings.
Subs: Ross White, Theo Bailey-Jones, Dan Holman.
Kidderminster: Danny Lewis, Jared Hodgkiss, Kyle Storer, Chey Dunkley, Jack Byrne, Marvin Johnson, Michael Gash, Reece Styche (Craig Reid 69), Aman Verma, Kevin Nicholson, Josh Gowling.
Subs: Jake Green, Nathan Blissett, Ahmed Obeng, Callum Gittings.
Referee: Adrian Holmes (Yorkshire)
Kidderminster: Gowling (24, foul), Storer (52, foul), Johnson (56, foul), Byrne (90, foul)