Arsenal moved top of the table – ahead of Manchester City – with the result, which surpasses the 9-0 win for Liverpool against Doncaster Belles in 2013.
Dutch forward Miedema, who was the top goal scorer in the division last season, also assisted four goals in an excellent individual performance at Meadow Park.
England duo Leah Williamson and Jordan Nobbs, Scotland international Emma Mitchell were also on the scoresheet, while Lisa Evans scored twice.
Miedema, who was shortlisted for the Ballon d’Or in October, created goals for Evans and Williamson inside the opening 10 minutes, before she scored three herself as the hosts led 5-0 at the break.
The 23-year-old scored her fourth and fifth goals either side of Nobbs’ goal, before she assisted Evans’ second and then completed her second treble inside 13 second-half minutes.
Mitchell added the 11th goal for the hosts, before the visitors scored a consolation goal through Yana Daniels with just six minutes to go, after Manuela Zinsberger saw her penalty saved.