With a five point advantage nearly midway through the first half, San Diego rattled off 10 straight points to open up a 27-12 lead with 7:56 left before the break.
Nick Kerr, who finished with 12 points on four first-half 3s, knocked down 3-pointers on three consecutive possessions as the Toreros pushed their lead to 19 about 2 1/2 minutes later.
San Diego (14-14, 5-10 West Coast Conference) led 44-23 at the half.
Pacific cut its deficit to 13 with an 8-0 run to open second half, but USD responded by scoring 11 straight.
The Tigers were out-rebounded 36-33 and shot just 38 percent, including 3 of 15 from 3-point range.