After a close first quarter, Purdy clung to a 12-11 lead.
"Our defense has been play extremely well the last few games," said Purdy coach Tommy Egan. "Tonight, we didn't shoot the ball well, but our defense put us in a position where we could overcome our shooting slump."
Purdy junior Cameron Terry came off the bench to score 4 points, but it was Terry's defensive spark that got the Eagles rolling. Terry pulled down seven rebounds, had three steals and disrupted the timing of the College Heights' offense with several tipped passes.
"Cameron had a great night," said Egan. "He is good team player and provides a lift for us off the bench."
The Eagles led 25-15 at halftime and only allowed 11 second half points.
Eleven players scored for Purdy.
"That is a major plus for our team," said Eagn. "Anytime you can get 11 guys to provide you with points you have to be happy."
Scoring for College Heights were: Spencer Ming, 7; Evan Belk, 5; Blake Roberts, Matt Wickland and Dagen Worthington, 4 each; and Matt Wickland, 2.
Scoring for Purdy were: Drew Williams, 13; Cody Hall, 9; Devon Bennett, 1; Garen Nelson, 6; Terry and Austin Hancock, 4 each; Brent Cornman, 3; Alex Haworth, Alex Mareth and Glen Scott, 2 apiece; and Tyler Scott with 1.
Purdy plays Liberal in the semi-finals on Wednesday at 6 p.m. Liberal hit a 3-pointer at the buzzer to earn a 55-54 victory over Miller.
In the other Class 2, District 12 semi-final, Wheaton plays Greenfield. The Bulldogs were 77-51 winners over McAuley. The Wildcats were 56-45 winners over Jasper. Tipoff is set for 4:30 p.m.