The Stars (33-20-4) had won their past five games and were 13-0-1 in their past 14 against the Canucks dating to April 12, 2013. Dallas holds the first wild card into the Stanley Cup Playoffs from the Western Conference, five points behind the first-place Nashville Predators in the Central Division.
"I think the hardest-working team won," Stars captain Jamie Benn said. "They jumped on us early. Three goals in the first is tough to come back from. We just didn't have our game tonight."
Boucher gave Vancouver a 1-0 lead 2:11 when he stole the puck from defenseman Dan Hamhuis behind the Stars net and banked in a shot off Ben Bishop's left pad. The call on the ice was no goal, but it was overturned after a video review.
"It was definitely nice to get a lead," Canucks coach Travis Green said. "And the type of goal. We talked about going to the net tonight and finding a greasy goal. It's not easy to score in the League if you're not willing to go to the net, and that was a good example."
Virtanen make it 2-0 at 11:38 when he beat Bishop on a breakaway.
"The concern for me is the odd-man rushes," Stars coach Ken Hitchcock said. "We're giving up more, which is a recipe for disaster. We tried to put the brakes on it and weren't able to, so now we've paid the price and this should get everybody's attention."
Vanek scored his 16th of the season at 13:27 on a slap shot to make it 3-0.
Bo Horvat gave Vancouver a 4-0 lead with a power-play goal at 4:41 of the second period. Bishop was pulled after allowing four goals on 20 shots.