With the win, Saint Mary's improves to 6-5-5, 5-2-2 WCC, while San Francisco drops to 6-9-2, 4-5-1 WCC.
"This was a playoff type atmosphere," said head coach Adam Cooper. "The guys played well today and we got the winning goal. Julian got a good service and Nate found an opening in the box... Nate won a ball and got us the victory."
The final play came at the beginning of the second OT. Justin Grider drew a foul near the right sideline about 30 yards out. Julian Godinez took the free-kick and served it up into the box. The box was cluttered with players from both squads and Arambula found an opening to the ball and headed in the goal, the first of his career for the junior defender.
For the game, Saint Mary's outshot USF by a 17-4 margin, including a 9-0 edge in the second-half.
Saint Mary's got on the board first in the 25th minute on a set piece. Godinez took the corner kick and Tom Mohoric was there to head in the go-ahead goal to give SMC the 1-0 edge.
San Francisco responded in the 40th minute off a set piece as well. Tanner Smith found an opening and head in the goal from the corner kick from Taylor Krueger to tie the game at 1-1. Saint Mary's outshot USF 5-3 in the first-half but the Dons held a 3-2 edge in corner kicks.
The Gaels dominated the second-half by outshooting USF 9-0 but SMC could not find the net as the squads headed to the first 10 minute OT.
USF played well in the first OT as the Gaels only mustered two shots compared to one by USF.
In the second OT, the Gaels held first possession and worked the offense to draw a foul which set up the free kick and Arambula's score.
Agustin Cazarez led the Gaels with three shots while Jose Cabeza, Godinez and Justin Howard took two shots each.
USF was led by Smith who took two of USF's four shots in the match.
Saint Mary's is back in action on Sunday, November 6 when it travels to Buck Shaw Stadium to take on Santa Clara.