Toronto outshot Vancouver 24-7 in the second period and 17-6 in the third period. Demko made two of his best saves midway through the third to preserve the lead, against William Nylander on a breakaway at 9:35 and against Ilya Mikheyev on a point-blank one-timer at 10:35.
"It doesn't matter what the circumstances are, I try to make as many saves as I can," Demko said. "The end result was good. That's all that matters."
Miller put the Canucks ahead 1-0 at 1:29 of the first period on a rebound from low in the left face-off circle with Mrazek out of position. Mrazek tried to poke check Bo Horvat, who was cutting across the low slot alone on the rush.
Boeser made it 2-0 at 6:00 on the power-play, scoring on a rebound at the side of the net after Oliver Ekman-Larsson's one-timer was deflected in front with Mrazek screened.
"We just lacked the intensity required to start the game," Keefe said. "Obviously we deserved a whole lot more goals than we got tonight, but that's what happens right? It's a team that relies on world class goaltending to win games, and you give them a two-goal lead and it's an uphill climb."
Matthews cut it to 2-1 with a power-play goal at 12:46 of the second period, one-timing a pass from John Tavares from the bottom of the right circle. Matthews has scored 14 points (seven goals, seven assists) during his streak.
"Unbelievable," Matthews said about the pass from Tavares, who was cutting across the top of the crease as he made it. "Just the poise, the patience to make that play. He put it right in my wheelhouse and I just got it off quick. That was all him, just an unbelievable pass, an unbelievable play."
Ondrej Kase tied it 2-2 with a power-play goal at 15:41, deflecting a slap pass from Jason Spezza over Demko's blocker from the slot.