Brock Zylstra added 14 points and Brandon Davies chipped in 12 points and eight rebounds for the Cougars (4-2) as they handed the Matadors (6-1) their first loss of the season.
Stephan Hicks led Northridge with 25 points and eight rebounds. Stephen Maxwell added 17 points and Josh Greene had 13.
The Cougars played with Jabari Parker, one of the nation's top high school recruits, in attendance. Parker made an official visit to the BYU campus on Saturday and the Cougars are one of five teams the Chicago native is considering playing for in 2013. Other schools Parker is considering are Duke, Stanford, Florida and Michigan State.
BYU next hosts Montana Wendesday night.