Kyle MacLean gave the Islanders a 1-0 lead at 5:56 of the first period. Following a scrum for a loose puck in the crease, MacLean was able to eventually lift the puck over a sprawled Blackwood.
The Avalanche challenged for goaltender interference, but the call on the ice stood following a video review.
Lee extended it to 2-0 at 18:20. Barzal found Lee inside the right circle for a wrist shot that beat Blackwood high glove side.
Horvat made it 3-0 at 6:58 of the second period on a rebound in the low slot off Matthew Schaefer's shot.
Adam Pelech then pushed it to 4-0 at 7:59 with a wrist shot from inside the left circle that beat Blackwood off his glove and in.
“We had some, like, strange reads,” Avalanche coach Jared Bednar said. “It cost us scoring chances and gains. We got outbattled in our netfront, too many rebounds, but they scored two goals and rebounds, some of them multiple rebounds, before it went in. And that can't happen. We got to be harder at the netfront, and we weren't tonight.
“They were competitive there, give them credit. I thought they played a really good game. I thought we fought and tried to stay with it. Some guys didn't have great nights and made some strange reads and made some mistakes that cost us, but more importantly, like that battle at the netfront, it has to be higher, quicker.”
Colorado scored two goals in a 1:25 span in the second to cut it to 4-2. Nichushkin deflected Sam Malinski's point shot at 8:39 before Necas’ cross-crease pass deflected off Travis Mitchell and in at 10:04.