The Canucks outshot the Kraken 18-4 in the second period.
"They won the races, they won the puck battles, and because of that they had the majority of the zone time," Seattle coach Dave Hakstol said. "You end up spending your energy playing defense and there's not much left to go in the other direction. The second period made the difference in this hockey game."
Bo Horvat scored 35 seconds into the third period with a one-timer from the left hash marks during a power play to make it 4-2. It was his second goal in nine games since returning from NHL COVID-19 protocol, which caused him to miss five games.
"There's no doubt he's been struggling since he got back," Boudreau said. "It's the monkey off your back type scenario, and it just alleviates a lot of pressure that you're putting on yourself, and hopefully that's what happens with him."
Pettersson, who had the secondary assist on Horvat's goal, has scored 17 points (eight goals, nine assists) in his past 15 games, including seven (one goal, six assists) in his past three, after beginning the season with 15 points (six goals, nine assists) in 36 games.
"I feel great. I think I'm creating a lot. I feel like myself out there. I'm playing with fun," said Pettersson, who missed the final 30 games of last season because of a wrist injury he said was still being taped up to start this season. "Definitely it was a slow start for me. It took me way longer than I wanted to this season, but in the last few weeks I feel like myself again."
Tanner Pearson shot into an empty net with 1:32 left for the 5-2 final.
NOTES: McCann, who was selected by Vancouver in the first round (No. 24) of the 2014 NHL Draft, played his 400th NHL game. … Giordano trails Mark Howe (28), Paul Coffey (20), Ray Bourque (16), Bobby Orr (16), Chris Chelios (13) and Red Kelly (12) for the most shorthanded goals by a defenseman in NHL history. Kelly scored 15 career shorthanded goals, but three came as a forward.