Lewis did most of his damage from 3-point range, making 7-of-16 from behind the arc. Coleman added 16 points for Houston (13-11, 5-5 Conference USA).
Derek Williams had 24 points to lead SMU (11-13, 4-6). Mouhammad Faye had 10 and Papa Dia just missed a double-double with nine points and 10 rebounds.
Even with Lewis' 50 percent shooting day (9-for-18), the Cougars struggled from outside, making just 32 percent of their shots. But Houston was 18-for-20 from the free-throw line, including the last eight in the final minute.