The Panthers were out front throughout with leads of 19-12 after one, 27-19 at half and 37-30 after three.
Jasmine Demers again led the way for the St. Mary's girls as she nearly turned in a triple-double with 18 points, 14 rebounds, seven assists and three blocks. She was 8-of-15 shooting.
Annie Flynn joined her in double figures with 11 points on 5-of-9 shooting. Emily Ivey had seven points and three assists, Riley Lenhart had six points and two rebounds, Rachel Todd five points and two rebounds, and Mackenzie Laven and Trisha Lenhart turned in two points apiece.
St. Mary's was 22-of-46 from the floor and 7-of-14 at the line.
"We started the game great with six different girls scoring in the first quarter," said St. Mary's head coach Jim Demers. "I think the girls are starting to feel more comfortable with our offense and what we're trying to do this year. We still need to improve a lot on the defensive side of the ball and with that, boxing out our girl for the defensive rebound. Jasmine was close to a triple double as I think she would rather have an assist over her scoring. I'm very happy and proud of all our girls."
G-T/R-A (3-2) was led by Brooke Hoffman's 24 points and five rebounds.
The Panthers return to action Friday night at Prairie Valley (2-2). They return home Tuesday to meet Sioux Central.