Sam Dower Jr. scored 24 points and Gonzaga made 11 of 12 free throws in the final 1:31 to hold off San Francisco 75-65 Saturday night.
The win gave the West Coast Conference-leading Bulldogs (20-3, 10-1) some breathing room between themselves and the second place Dons, whom Gonzaga beat 69-41 during the first round of conference play on Dec. 30.
Gary Bell Jr. finished with 13 points for the Zags, who shot just 38.8 percent for the game. They came into the contest shooting 51.1 percent from the field, 2nd in the nation.
Przemek Karnowski added 12 points and eight rebounds.
GU used a 20-7 run, during which Dower scored nine points, to open up a 54-40 lead with 9:17 to play.
Avry Holmes, who finished with 18 points, pulled San Francisco (14-9, 7-4) within 63-57 with just more than 2 minutes remaining but the Dons would get no closer.