Ellie Seedhouse scored three powerplay goals, but a 3-0 lead built through the 35 minutes was too much for the Mustangs to overcome on Friday night at the Seymour-Hannah Centre in St. Catharines, Ont.
Jessica Ulrich made 24 saves in the loss.
On Sunday, Western dropped a 2-0 decision in Guelph.
The Mustangs (3-6) return to action on Nov. 13 at Windsor and then play at York and Toronto Nov. 20 and Nov. 21 before returning home Nov. 27 to host Laurier at 4 p.m. and Nov. 28 to host Waterloo at 2 p.m. at Thompson Arena.