Pettersson, playing his 100th NHL game, tapped in another backdoor pass from Brock Boeser on a power play to make it 3-0 at 13:58. Pettersson has 98 career points (40 goals, 58 assists), but failed to join Pavel Bure (111 points; 64 goals, 47 assists) as the only other player to reach 100 points in their first 100 games with Vancouver.
MacEwen scored his first NHL goal on a deflection in front to increase the lead to 4-0 at 17:23.
"A huge weight off the shoulders," said MacEwen, a 23-year-old forward playing his 11th NHL game. "Being up here the last couple of weeks, getting in a few games and getting some chances, just to get the first one, it feels amazing."