Chandler Stephenson made it 2-0 on a 3-on-2 power-play rush at 8:53 of the second period, one-timing a pass from Jordan Eberle past Demko’s pad from the left face-off dot.
The goal came shortly after the Canucks failed to get a shot on a shorthanded 2-on-0, with Drew O'Connor fanning on a one-time attempt off a return pass from Kiefer Sherwood.
Sherwood cut it 2-1 with a power-play goal at 13:06. He got the rebound of DeBrusk's point shot off of Daccord and put it past the goaltender with a snap shot.
Ben Meyers gave Seattle a 3-1 lead off the rush at 18:13, driving the net on the right side to tip a Ryan Winterton pass over Demko's blocker in tight.
Winterton, along with fellow fourth-line forward Jacob Melanson, who had the secondary assist on Meyers' goal, each extended his point streak to three games. Melanson has three assists in his streak, and Winterton has one goal and two assists during his run.
"'Mel' made a nice play coming out of our own end and then 'Wints' was able to skate it all the way in and made a great play finding me," Meyers said. "We're just focused on playing simple and being hard to play against, and things are working out and we're finding success just doing the simple things right."
DeBrusk, who was a healthy scratch in Seattle on Dec. 29, scored on a backdoor power-play pass off his skate at 19:22 to make it 3-2. It was DeBrusk’s first goal in eight games and his first multipoint game of the season.
“It’s better in a win,” DeBrusk said. “We didn't win. Everyone likes to judge people on points. It's easy to say that when you have a couple points in the game, but we lost.”
Karlsson, who signed a two-year, $4.5 million contract ($2.25 million average annual value) on Friday, swept a rebound under Daccord’s pads with a backhand from the top of the crease to tie it 3-3 at 6:15 of the third period.
“I love to play here,” Karlsson said. “I'm really excited for two more years in the organization. I really appreciate everyone here, and it's a lot of fun to play here, so I'm really excited for the future.”
NOTES: Eberle’s assist extended his point streak to six games (seven points; four goals, three assists). … Vancouver was 4-0 in the shootout, with goalie Kevin Lankinen stopping all 17 shootout attempts this season. … Sherwood has 17 goals, two short of matching his NHL single-season high of 19, set last season.