Johnnie Bryant iced the game when he got behind the Ram defense and took a cross-court pass for an easy lay-up with just 1.7 seconds left.
Bryant scored 17 and dished out seven assists, while Luke Nevill scored 18 to lead all scorers.
Nevill led the Utes with five rebounds.
Shaun Green added 15 points.
Jason Smith led the Rams with 17 points, Tyler Smith scored 16.
Despite allowing the Rams to shoot 62.8% from the field, Utah scored 54 second half points and made enough plays late in the game to hold off the Rams.
Down two in the final minute, CSU pressured Nevill in the backcourt and forced him to throw a bad pass. Somehow Bryant was able to dive and guide the ball to Ricky Johns, who made a lay-up that gave the Utes a 78-74 lead.
Johns added two free throws to give Utah some cushion. Tim Denson hit a three-pointer for the Rams to cut the lead to three.
The loss is the fourth straight for the Rams. It was the first second half comeback for Utah since they beat Rice on November 25th.