Foster had 10 rebounds to complete the first double-double of his career. Raymond Cowels III had a season-high 17 points, including five 3-pointers. Evan Roquemore added 10 points. Marc Trasolini had a team-high 11 rebounds for the Broncos (13-6, 2-3 West Coast).
The Broncos led 35-24 at halftime. The Broncos shot 50.8 percent from the field for the game, while San Francisco shot 32 percent.
Matt Christiansen had 12 points for San Francisco. Mark Tollefsen had a team-high five rebounds.
The Dons (7-11, 0-5) have lost five consecutive games.
The Broncos also defeated the Dons 74-69 on Jan. 2.
The game Thursday was the 212th meeting between San Francisco and Santa Clara. Santa Clara leads the series 111-101.