Brenna Moss hit a bases-loaded triple in the top of the seventh inning to provide for the winning margin.
Michelle Moses got the win in the circle striking out eight Bruins.
Bulldogs improve to 9 and 5 this year.
The other Diamond Dogs made snapped their short two game losing streak in Malibu on Saturday, beating Pepperdine 8-4.
Buchanan grad Jordan Luplow hit a bases-loaded double to cap a four-run fourth inning. Cody Kendall got the win on the mound.
They wrap up their series Sunday afternoon at 1 p.m.