Morandais scored 24 points, including a tiebreaking 3-pointer with 1:58 left that triggered a 13-0 run, and Colorado upset No. 3 Texas 93-80 on Tuesday night.
Colorado (13-7, 3-4 Big 12), which beat a Top 10 team for the second time in 13 days, also got 23 points from Blair Wilson and 18 points and 14 rebounds from Stephane Pelle.
The Buffaloes, who beat then-No. 6 Kansas 60-59 on Jan. 22, broke open a second half that had 19 lead changes with their flurry over the final two minutes.
After misfiring from the free throw line most of the night - hitting only nine of their first 20 - the Buffaloes went 12-of-14 over the final 3:19.
David Harrison, who had 16 points, hit two free throws to give Colorado an 80-74 lead with 2:50 remaining. Until those foul shots, neither team led by more than four points in the second half.
The Longhorns countered with six straight free throws - four by T.J. Ford - to make it 80-80 with 2:14 to go.
Morandais' 3-pointer from the left side was followed by his steal and a subsequent free throw by teammate Antoine McGee.
After Morandais blocked a shot, he stole an inbounds pass and was fouled, making both free throws for an 86-80 lead with 1:05 left.
While the Longhorns were missing desperation 3-pointers, McGee and Wilson each hit two more free throws, and Harrison's fastbreak layup made it 92-80.
"Coach always talks about how we have to step up," Morandais said. "It happened to be me tonight."
Morandais, a 6-foot-5 swingman, also played at point guard and helped put the clamps on the electric Ford, who had 15 points and eight assists.
Colorado coach Ricardo Patton said "rebounding and transition defense were the keys for us. This is the best effort that we've had, particularly from the guys who played the bulk of the minutes. If all of our guys show up on the same night, we have a chance to be a good team."
Fans stormed the court after the win, which snapped Colorado's six-game losing streak in the
Although it was close until the finish, Barnes said, "I thought they beat us every way you could beat a basketball team. They beat us on the boards, they beat us with their shots and they played great defense when they needed it. They beat us in every area, from the coaching all the way down."
Colorado outshot the Longhorns 49 percent to 42 percent, helping offset 21-of-34 shooting from the line.
Texas built a 12-point lead in the first half but Colorado cut the deficit to 40-38 at halftime.
While Colorado was 1-of-8 from the field to start the game, Texas took an 11-3 lead, including five points by Sydmill Harris.
Colorado trimmed the deficit to four points on Lamar Harris' dunk with 10:06 left in the half, but the Longhorns scored the next seven points, five by Mouton, for a 29-18 lead.
Ford's two free throws made it 31-19 before Colorado went on a 12-2 run. Blocked shots by Pelle and Harris ignited the comeback, and Morandais, who had 12 points in the half, hit consecutive 3-pointers.
Wilson's steal and layup on a goaltending call made it 33-31, but Colorado's bench was charged with a technical foul during a timeout, and Ford started a 6-0 run with two free throws. Thomas had a tip-in and a dunk as the Longhorns pushed their lead back to 39-31.
Wilson's 3-pointer and Pelle's short jumper on a second chance helped cut the deficit to two at halftime.