The Cougars, who entered the season ranked for the first time since starting the 1983-84 season at No. 3, shot 42% from the field. Houston finished 13 of 33 on 3-pointers and outrebounded the Cardinals 49-34.
Anderson Kopp scored 15 points and Avery Sullivan added eight points and seven rebounds to lead Lamar. The Cardinals shot 30%, including 1 of 13 on 3-pointers.
Playing in front of a 25% capacity crowd, the Cougars started slowly before finishing the first half on an 18-4 run to take a 35-15 lead into halftime. Sasser scored nine of his 19 first-half points during the run.