Boeser carried the puck into the Penguins zone before shooting from the left face-off circle past forward Jake Guentzel and over Casey DeSmith. He has seven points (six goals, one assist) in three career games against Pittsburgh.
"Every time you play those special players on the other team, maybe you get fired up a little bit more," Boeser said. "I don't know what it is. It's always special playing those guys."
WATCH: [All Canucks vs. Penguins highlights]
Carl Hagelin forced overtime with a goal that tied it 2-2 at 16:46 of the third period. Phil Kessel led a 2-on-1 before passing to Hagelin, who tapped a shot past Anders Nilsson for his first goal of the season.
Nilsson made 26 saves for Vancouver (4-2-0), which has won three straight games after losing two of its first three.
"It's nice to see the character we have in this group," Nilsson said. "So it's really fun to stand back there now and see how we work, especially against good teams like tonight, how hard we kind of wore them down and put pressure on them throughout the whole ice. For them, you see they're frustrated and it's tough for them to create scoring chances even with that skill they have."