Houston started hot and held on to hand No. 18 UCF their first loss of the season on Saturday night.
The Cougars jumped out to a 36-21 lead in the first half and held on for a 76-71 victory.
"We've got a dream here that we want to fill this place up," first-year coach James Dickey said of Hofheinz Pavilion. "But in order to do that, you've got to win big games."
It was Houston's first win over a ranked opponent since 2005.