Hayden Partain's first-half goal secured all three points at home for Republic FC on Saturday night.
The Indomitable Club fall to the Foxes in the final Highway 99 Derby of the regular season.
Sacramento were held scoreless for the first time in over two months, fallingl 2-0 on the road to Reno 1868 FC.
Braces from Iwasa and Bonomo lead Republic FC to their largest margin of victory in club history.
Republic FC’s run in the U.S. Open Cup comes to an end after a valiant effort in San Jose.