Daviyon Draper added 11 points and a career-high 15 rebounds for the Panthers (7-7), who had a 46-25 rebounding advantage. Diaz made 6 of 8 shots and 11 of 17 free throws, grabbed 15 rebounds and blocked three shots, the 18th straight game he has blocked a shot.
Florida International led 30-26 at the half but Diaz, who had just three points at the break, scored 16 of the Panthers' first 18 points in the second half as they steadily pulled way with 56 percent shooting (14 of 25). They also made 17 of 22 free throws in the second half.
Solomon Poole had 15 points, hitting four 3-pointers, for the Owls (2-12), who lost their seventh straight. They shot 38 percent and 9 of 18 from the line.