Anders Nilsson made 25 saves for the Canucks, who were coming off a 4-1-0 road trip.
Markus Granlund scored with 1:17 left in the first to give Vancouver a 3-0 lead, and Baertschi got his 100th NHL point when he deflected a Derrick Pouliot shot past goalie Braden Holtby on the power play at 9:41 of the second period to make it 4-0.
Derek Dorsett scored his Canucks-leading sixth goal on a wraparound with five minutes left in the second to make it 5-0 and chase Holtby, who made 17 saves on 22 shots.
"When you come off a long road trip, sometimes it's a letdown, but we stayed fresh," Dorsett said.
Evgeny Kuznetsov scored his first goal of the season to make it 5-1 at 15:17 of the second.
The Capitals (4-5-1) have lost four of their past five games.
"We've got some work to do and I need to get better," Holtby said. "There's a lot of things we need to work on. Finding our identity is the main thing. We are still playing like our team from last year. We knew it wasn't going to come easy, it wasn't going to come quickly, but we are far enough into the season now that we are not going to use the excuse of being young and different anymore. It's time to start performing and that includes myself."