Conor Garland had a goal and an assist, and Brock Boeser scored on the power play for the Canucks (2-2-1), who lost their previous two games.
"It was a good bounce-back game," Demko said. "There was some stuff we wanted to clean up from Buffalo (a 5-2 loss Tuesday). It's a good 60 minutes, I thought. We sustained our style for the full 60, which is something we're trying to evolve with. A lot of good things tonight.
"I think 'statement' is actually the perfect word for it. We're not trying to prove anything to anyone outside off our room, but it's important for our group to all be on the same page with that stuff. I think that's where the standards come from. Last year wasn't good enough for our group. We need to make sure that we're not falling into those patterns again."
Alex DeBrincat scored for the Blackhawks (0-4-1) who have been outscored 17-3 at 5-on-5 and have not held a lead for 300:57. Kevin Lankinen made 21 saves.
"We've got to shoot the puck more, got to be at the net, give ourselves a chance to score a dirty goal, let the puck go in off you, create a rebound," Chicago coach Jeremy Colliton said. "When they're pinching their D, let's win a puck battle so we can create a 2-on-1. We were pinching our D the first three games and they were winning battles and going 2-on-1 the other way. We can do that too. There's little things you can do and ultimately we've got to give ourselves a chance to get a bounce.
"I feel like we haven't generated enough of those second opportunities, those deflections, those rebound goals. Not enough pressure around the net and then when you have it there, you've got to put the puck there. That's something we've talked about."
Jason Dickinson gave Vancouver a 1-0 lead at 6:36 of the first period from the left circle following a pass from Matthew Highmore, who was acquired in a trade with Chicago in April.