The Quebecois side was thoroughly humiliated in Colorado as the Impact were routed by the Rapids.
The Rapids set the tone early with a fifth-minute goal. Montreal's Sanna Nyassi pulled Edson Buddle down from behind as the forward was shooting, and Dillon Powers put the penalty kick straight down the middle to make it 1-0.
Two second-half goals in quick succession put the game beyond reach. Kamani Hill curled an impressive goal from the corner of the box past Troy Perkins in the 54th minute to make it 2-0.
Four minutes later, Shane O'Neill scored his first career MLS goal. Collecting a hashed clearance 25 yards from goal, O'Neill teed up his strike and buried it in the top corner.
Dillon Powers picked up his second goal of the game and made it 4-0 with a goal in the 84th minute. Collecting Marlon Hairston's squre pass inside the box, Powers turned and picked out the far low corner.
Andres Romero notched a consolation goal for Montreal in the 88th, dashing through the Colorado defense and turning Chris Klute before sliding his shot inside the far post from decent range.
Colorado is now 5-4-3, in third place in the Western Conference. Montreal is 10th in the East, its 1-6-4 record the worst in Major League Soccer.