The late scoring spurt broke open a tight 29-27 game after three quarters, after the host Rams had eased to a 22-20 halftime lead.
Courtnie Voss led the Pirates with eight points in the low-scoring contest, while teammate Heather Joslin added seven, and Breanna Mathes five.
Mathes also led G-H on the boards with seven rebounds, while Joslin grabbed six, and Victoria Andresen five. Joslin also led in steals with four.
The Pirates sank just 13-51 field goals for an icy 25 percent, and was 4-10 from the free throw line. MVAO netted 20-57 shots for 35 percent, and converted 2-9 free throws.
"This game came down to giving too many second chances," said G-H coach Ken Slater. "Our defense was all right on the first shot, but MVAO had 15 offensive rebounds and made many of them count on the second or third try as they pulled away from us in the fourth quarter. We played pretty evenly with them until that fourth quarter.
"The girls played hard and moved the ball better versus the zone, but we struggled getting the ball in the hole from close range. Courtnie was a bright spot for us offensively, knocking down four first-half perimeter shots. Breanna also showed some hustle throughout the game and came up with some strong boards for us."
The G-H boys and girls teams now break for the holidays and return Jan. 6 to host neighboring River Valley in the WVC twin bill.