Merthyr suffered injuries to Jason Welsh and Steve Williams
during a first half of missed opportunities with Luke Jones
’ shot cleared off the line and Andrew Thomas
’ header coming back off the crossbar.
The home side stayed on level terms until Kris Leek struck with a low 20-yard drive on 73 minutes to give goalkeeper Matt Bath no chance.
The home side saw late appeals for a penalty turned away as Thomas clashed with Sam Collier on the edge of the box but it was Merthyr who deservedly progressed into the next round.