Gabriel Bourque's shot from the left circle, his second goal in 50 games this season, gave the Avalanche a 4-2 lead at 17:10.
"At first I tried to look for a pass and everybody was open so I just tried to shoot high blocker and it went in," said Bourque, whose other goal was into an empty net March 9 against the Buffalo Sabres. "I don't think anyone is counting on me to score goals but I work every night to try and get one. Today it finally happened, so it's nice."
Tuch converted the rebound of Mark Stone's point shot at 16:37 to bring the Golden Knights within 4-3, and they had a power play for the final 7.6 seconds after MacKinnon was assessed a holding-the-stick penalty.
"Obviously we made it interesting there," Barrie said. "They're a good team and they've been playing really well lately so it's not a surprise they were going to give us a push at the end. We showed a lot of character to kind of grind that one out."