Boston Town suffered a 2-1 home reverse on their return to action.
After three postponed fixtures, in-form Harborough proved too much for the Poachers at the DWB Stadium.
Despite seeing Tony Bartlett sent off after just 12 minutes for a foul, the Bees took a 2-0 lead via Ben Williams and Gladman Barnes.
Fraser Bayliss pulled one back for the Poachers, but they were unable to claim a point.
Town travel to face Sleaford Town on Boxing Day (KO 2pm).