Sir Alex Ferguson saw his son Darren get a straight red card in this tough clash at the Racecourse.
The Wrexham midfielder appeared to stamp on JJ Melligan after 63 minutes and referee Scott Mathieson had no hesitation in sending him off.
Wrexham thought they should have won this game as they made many chances, hit the woodwork twice, and had efforts cleared off the line.
Kidderminster notched their first win in seven games, thanks to two splendid goals.
Wrexham-born Sean Parrish was their hero. He made an early clearance to deny Andy Morrell a goal and then just before half time he hit a 25-yard left foot shot into the top corner beyond the reach of keeper Kristian Rogers.
The Red Dragons made a match of it when they were down to ten men for the last half hour, but a fabulous goal from Melligan three minutes from time ended any hopes the Welsh side might have had of getting a point.
He latched on to a loose ball on the right edge of the penalty area and hit a tremendous shot into the top right corner.
Wrexham's Paul Barrett hit the post early on after Lee Jones mis-kicked and then Morell was denied a goal as Stuart Brock made a fine diving save.
Kidderminster took the game to Wrexham at every opportunity and Dean Bennett was set up by Melligan for a shot keeper Rogers stopped at the foot of the post.
Harriers boss Ian Britton said: "We started well and carried it through. We could have had three goals in the first half. We haven't got to fear anybody in this League.” Wrexham manager Denis Smith said: "I don't like losing, I never have done. When you break things down we had the better chances but we haven't put them away."