Counties stormed ahead in the first half with two converted tries from Portia Woodman and Renee Wickliffe also diving over to take her side 19-0 into the break.
Woodman completed her hattrick early in the second half before it was all Manawatu pressure. Sarah Goss powered over shortly followed by Kristina Sue.
Counties were down to just five players at one stage allowing Sue to touch down for her second try late on, but it was too little, too late.