Nathan MacKinnon scored twice as Colorado, the Presidents Trophy winner, jumped out to an early series lead against the 2019 Stanley Cup champions.
Story of the game
Around midway through the first period, Brayden Schenn threw a knee-on-knee hit to Mikko Rantanen and after Ganriel Landeskog wiped out Schenn, both players served five-minute penalties for fighting.
Ryan O'Reilly would be sent to the penalty box for tripping MacKinnon and the Avalanche cashed in on the power play as Cale Makar weaved past Blues defender Tyler Bozak and beat Jordan Binnington to give Colorado a 1-0 lead.
The Avalanche had more quality chances through the remainder of the first period, but Binnington kept them at bay to keep it 1-0 after the opening 20 minutes.
Binnington robbed Rantanen after a slick feem from Nazem Kadri and St. Louis tied the game when forward Jordan Kyrou buried a one-timer past Colorado goalkeeper Philipp Grubauer. That was the only notable action from the middle period and the game was 1-1 through two.
Rantanen worked hard down low and gained the puck, feeding a streaking MacKinnon, who beat Binnington from the slot to give the hosts a 2-1 advantage.
The Avalanche doubled their lead after killing off a power play following a Ryan Graves tripping penalty. MacKinnon lasered a shot from the point that was tipped home by Landeskog to make it 3-1. MacKinnon added an empty-netter to wrap up the scoring.