Matt Williams added 12 points and Staphon Blair 11 for the Knights (12-17, 4-14 American Athletic Conference), who won for only the second time in their last six games.
Jherrod Stiggers led Houston (16-15, 8-10) with 22 points and Danuel House added 18. L.J. Rose finished with 16 points and 10 assists for the Cougars, who had won four straight.
UCF led 50-32 at halftime and was never seriously challenged the rest of the way. Houston cut the deficit to 14 on three occasions in the middle of the second half, but each time, UCF answered with a 3-pointer. The last one came from Walker, who followed that with a 3-point play to push the Knights' advantage to a comfortable 72-52 with 9:58 left in the game.
Walker, who didn't score in the first half, hit five of six shots from the field and eight of nine from the free throw line during his second half run.
The Knights nearly ran Houston off the court in the first half, jumping out to a 25-point lead in the first 13 minutes before settling for a 50-32 halftime lead.
Sykes had 16 points and, for one of the few times this season, got plenty of support. Newell had eight points and Spurlock and McBride six apiece as UCF had its best offensive half against a Division I opponent all season.
The Knights shot 54.3 percent, had six 3-pointers, went 6 of 6 from the free throw line and turned eight offensive rebounds into 10 second-chance points.
UCF started the game with a 20-4 burst, pounding Houston inside and out. A 3-pointer from Spurlock gave the Knights a 36-11 lead with 7:04 left in the half, fueled in part by a 20-7 rebound advantage.
Houston was lethargic the entire half especially at the offensive end. The Cougars had six turnovers and one assist the first 11 minutes, during which they scored only one field goal and six points.
Houston finally got untracked late in the half. Back-to-back 3-pointers by Stiggers in the final 1:15 helped the Cougars get the deficit under 20 before halftime.