The game took place with former Frog basketball player M.E. Chappell celebrating his 98th birthday by sitting in the first row behind the TCU bench. Chappell lettered for the Frogs in the early 1930s and is the oldest living former TCU basketball player and current season-ticket holder.
Chappell was recognized in a halftime ceremony that included a taped birthday greeting from the TCU basketball team.
Mitchem's previous career-high was 16 points last year at Air Force. He was 6-of-8 from the field, including 5-of-7 behind the arc in a career-best 37 minutes.
TCU led 34-31 at the intermission and scored the first six points of the second half, jumpstarting the Frogs on a 22-7 run to lead 56-38 on a Kevin Langford dunk with 13:15 remaining.
Langford's 16 points give him 985 in his career and leave him just 15 shy of becoming the 29th player in TCU history to reach the 1,000-point milestone. He added a team-best eight rebounds.
Buljan's 18 points were one shy of a career-high 19 set last month at Indiana. Ruzgas had 10 points as four Frogs scored in double figures.
A 3-pointer by Kevin Butler gave TCU its largest lead of the game at 64-45 with 7:47 to play.
The Rams would not get closer than 11 points the remainder of the contest.
The Frogs shot 65.4 percent (17-of-26) in the second half to finish the game at a season-best 53.7. TCU held a 34-27 rebounding advantage.
The Frogs trailed by as many as seven points in the first half before going on a 13-2 spurt to lead 27-23 on a Buljan layup with 4:11 left.
Willis Gardner led Colorado State with a game-high 23 points. Marcus Walker added 16, including four 3-pointers.
The Frogs' 81 points represented a season-high.
At 9-5, TCU is off to its best start since beginning the 2006-07 campaign with a 10-4 record.