From the start of the game, Colorado showed no quit despite frustrating outcomes and not getting results. They found themselves trailing 1-0 after the first period, but responded with a dominant second period effort.
In the opening frame, Colorado put forth an opportunistic effort including a 9-7 shot edge and hitting three posts, but fell 1-0 to the Blues heading into the first intermission.
Colorado and St. Louis exchanged chances early on with the Avs generating some promising looks from Nathan MacKinnon in tight, a look from distance from Sam Girard and a clapper from Nazem Kadri that wrung off the crossbar. But at 6:25 into the frame, an d-zone outlet pass from Cale Makar deflected off the skate of St. Louis forward Brayden Schenn and popped out in the low slot to O'Reilly where the former Avalanche centerman roofed his backhand over Kuemper to provide the game's icebreaker.
Down a goal, the Avalanche still produced some lethal looks including a shot from Artturi Lehkonen that hit the post on the shift after O'Reilly's goal and a slot in the low slot from Mikko Rantanen that also struck iron.
Colorado ushered a dominant response in the second period where they took a 2-1 lead with strikes from Nichushkin and Girard. The Avs came out firing in the middle frame - where they finished with a 20-9 shot advantage - and capitalized.
At 3:14, Rantanen centered a shot to the netfront that deflected off MacKinnon and fell to the backdoor. Nichushkin circled in and buried the loose puck over Binnington's stick. With the score tied 1-1, the Avalanche only continued to press. Binnington had to come up with a stop on a Devon Toews backhander in tight and made a goal line save on an Erik Johnson backdoor attempt, but Colorado finally struck again at 11:32.
Girard, who had a strong performance, unleashed a slap shot from the point that beat Binnington far side to give Colorado a 2-1 lead.