A goal in either half was enough to give the Shrimps the victory over a spirited, under-strength Harriers side who fought to the death with a last minute goal from midfielder Gavin Hurren ensuring a fraught final few moments for the home side
After a tight opening half played in atrocious conditions, it was Morecambe who struck first thanks to a controversial penalty when Harriers keeper Scott Bevan was adjudged to have brought down Gary Thompson.
After protestations from the Harriers players who had seen a good shout for a penalty themselves waved away when Andy White was sent sprawling by Steven Drench, Wayne Curtis stepped up to coolly blast his spot-kick home.
If Bevan was at fault for the penalty he more than made up for his mistake with a string of fine second-half saves.
On 49 minutes he reacted sharply to tip away a shot from Michael Twiss that was heading for the top corner and then made equally good stops from Thompson and Fraser McLachlan as Morecambe played some fine flowing football in the second period.
They were finally rewarded for their efforts by a second goal 16 minutes from time.
Again Thompson was the spur after being put through down the right. His cross seemed to have evaded everyone but Twiss ran in at the far post to drill a fierce left-foot shot past Bevan's right hand.
To their credit Kidderminster hit back strongly with Russell Penn volleying over from close range after a right-wing corner before they scored their late goal which set up a pulsating finale.
Jeff Kenna swung in a deep cross from the left and Hurren stole a march on his marker to squeeze his volley between Drench and his near post to give the home crowd some nervous moments.
The four minutes of added time added to those nerves but in the end Morecambe held on to progress into the next round.