Collinsworth also had 11 rebounds and four assists.
Anson Winder scored 15 on 5-of-7 shooting for the Cougars (21-8, 11-5 West Coast), who avenged a Jan. 24 loss at San Diego.
BYU led 33-28 at halftime and scored 14 of the first 16 second-half points to open up a 17-point advantage with 14:37 left.
San Diego (14-14, 7-9) pulled within 71-62 when Marcus Harris hit 1 of 2 free throws with 1:32 left, but got no closer.
BYU outrebounded the Toreros 38-23 and made 23 of 27 free throws. San Diego converted just 11 of 18 (61.1 percent) from the stripe.
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