All the action happened within 11 minutes as Rigg and Reeves scored on 58 and 60 before Town fought back thanks to a brace from James Gray in the 66th and 69th minutes.
The result leaves the Cobblers in eleventh place but just four points off the play-off places with all to play for in the final six games.
They are next in action on Easter Monday when Cambridge United are the visitors to Sixfields. The U's lost 2-0 at home to Bury on Friday.
The attendance was 4667.