With the win, Saint Mary's improves to 11-4, 3-0 West Coast Conference, while Gonzaga drops to 12-5, 2-1 WCC.
Saint Mary's was led by the duo of Jackie Nared and Danielle Mauldin. Both combined to go 4-for-4 from the free-throw line in the final seconds to push the Gaels to victory. Nared finished the night with 17 points and nine rebounds, while Mauldin finished with 12 points and a career-high tying 17 rebounds.
Kate Gaze added 12 points while Morgan Hatten finished with eight points and six rebounds.
Gonzaga was led by Sunny Greinacher with 12 points and seven rebounds, while Haiden Palmer and Taelor Karr had 11 points apiece.
For only the second time this season, the Gaels were out-rebounded as GU led 49-44, including 22 offensive rebounds for the Bulldogs.
Saint Mary's led by as many as nine points in the first-half and led 29-24 at halftime.
In the second half, Gonzaga raced out to a 10-0 run and led 34-29. The Bulldogs built an eight point lead at 46-38 with 8:01 left.
GU led 48-43 before the Gaels started to chip away. Mauldin pulled SMC within 48-45 with 5:01 left and Carli Rosenthal sank two free-throws to pull SMC within one point with 4:31 remaining.
Gonzaga held the lead at 51-48 with 2:53 remaining before the Gaels made their end of the game run. Gaze scored a key jumper from the baseline to pull SMC within one point with 2:24 left. The teams would remain at 51-50 GU, until under a minute remained. After alternating defensive stops, Mauldin grabbed a key offensive rebound and was fouled. Mauldin sank both free-throws to give SMC the 52-51 lead with 17 seconds left.
GU missed a shot and Nared grabbed the rebound and was fouled. She sank both free-throws to give SMC the 54-51 lead with seven seconds left. GU raced down court but Karr's three-pointer was off the mark and the Gaels had the victory.
Saint Mary's is back in action on Thursday, January 17 when it hosts San Diego at 7:00 p.m. in McKeon Pavilion.