Bryce DesArmo had four 3-pointers and scored 23 points, helping Castle Rock to its first win of the season.
Stevenson, trailing by one late, missed a shot. Castle Rock made two free throws, then Stevenson missed a 3-pointer at the buzzer.
Austin Brannan scored 32 points and had 11 rebounds for Stevenson. Isaac Hoidal had 10 boards for the Bulldogs.
CASTLE ROCK 55, STEVENSON 52
CASTLE ROCK — Connor Edwards 13, Bryce DesArmo 23, Parker Patching 2, Dakota Golden 11, Josh Belcher 0, Hunter Jansen 0, Dylan Holborn 6. Totals 21 (7) 6-11 55.