Spain scored the first eight points for San Diego State (7-1), which took the lead for good midway through the first half en route to its sixth straight win.
San Diego (4-4) suffered a major loss when leading scorer Brandon Johnson suffered a ruptured left Achilles tendon late in the first half.
Johnson, who scored 10 points, moved into fourth place on San Diego's all-time scoring list. Gyno Pomare led the Toreros with 17 points and moved past Johnson into the No. 3 spot on the list.