Andre Burakovsky led the way for the Avalanche with a goal and three assists. Valeria Nichushkin (1+2) and Nazem Kadri (1+1) also had multi-point efforts, while Samuel Girard, Nikita Zadorov, and Mikko Rantanen all added goals.
Colorado entered the night having scored a league-best average of 3.64 goals per game. Ralph Krueger spoke prior to the contest about the Avalanche's speed and tendency to attack with four players on the rush, elements the Sabres handled well early. Shots were in Buffalo's favor, 10-1, through the first 10 minutes.
Odd circumstances led to Colorado's first goal, scored with 6:48 left in the opening period. A shot hit off the leg of Rasmus Ristolainen, sending the puck toward the right corner. The Sabres' other defenders thought the puck had stayed near Ristolainen, who was boxing out two defenders to the left of the net.
With all eyes on Ristolainen - other than those of Jeff Skinner, who tried to warn his teammates of the puck's location - Girard pounced on the loose puck and buried it. Burakovsky scored on an odd-man rush less than a minute later.
Reinhart's goal - a deflection with nine-tenths of a second remaining - could have swung momentum. Instead, mistakes piled up in the following period.
"What happened then the next 20 minutes (is) truly unacceptable, and we have to do a deep dive on that," Krueger said. "Really disappointed. The goal that we scored at the end of the first seemed to bring us back into that start. Our inability to deal with their speed and their transition for that period of time, we seemed to be well prepared for it.
"I thought we began by playing the game we wanted to play, but we just deserted it. The final result is what it is. It's a slap where you need some more time than what I've had right now to digest. Again, we have no time for a big recovery. But, yeah, we're very disappointed right now and quite an unacceptable result."