The Illini were ousted in the opening weekend for the second straight year.
The fifth-seeded Cougars, who lost their two best players to season-ending injuries, are headed home to Texas for the next round, which will be in San Antonio, about a three-hour drive from Houston.
Kyler Edwards added 15 points for Houston, a team often overlooked but making major noise again this March.
For Illinois, it's another year of deep disappointment. The Fighting Illini were led by All-American Kofi Cockburn's 19 points.