Rantanen extended the lead to 3-0 at 10:32 on another 5-on-3 power play when MacKinnon's one-timer went wide of the net but bounced out to the other side, stranding Delia and leaving Rantanen with an empty net from a sharp angle.
"Mikko has ramped up his work ethic here game by game and he's found a way to make a difference," Bednar said. "He's playing with a lot of confidence again."
Pettersson made it 3-1 at 12:32, deking to his backhand in tight after being left alone at the top of the crease.
Brad Hunt scored on a one-timer from just inside the blue line at 19:27 of the second for the 4-1 final.
"It's hard to win games if we're all going to chase the game," Pettersson said. "But I know this team, we don't quit, and we don't quit for Bruce either."
NOTES: MacKinnon has 699 points (255 goals, 444 assists) in 671 NHL games, one point from becoming the sixth Avalanche player with 700 points, and the first player selected in the 2013 NHL Draft to reach that milestone. He has 15 points (four goals, 11 assists) during his seven-game point streak. … Colorado forward J.T. Compher has one goal and four assists during a three-game point streak. … Canucks forward Bo Horvat has his point streak end at nine games (four goals, six assists).