The four-goal margin of victory is the largest for the Americans in their long and historic rivalry with Canada over 48 World Championship games and 18 more at the Olympics.
Oettinger stopped 26 of 27 shots after entering the game early in relief of the injured Anthony Stolarz.
"As a backup goalie, you never know when you’re going to get your opportunity," Oettinger said. "I felt terrible for Anthony, and I hope he’s doing okay, but once I was out there I just had to get ready and do whatever I could to get into the game. The guys did a good job in front of me. They made it easier and really helped me get into the game. I can’t say enough good things about how they played today. They helped me settle in and it was a really good win for our team."
It gives the U.S. a 1-1 record in Group B, but more significant it makes Canada 0-2 for the first time ever in World Championship or Olympics play going back to 1920.
"It's a huge win," said Trevor Moore, who scored two goals for the winners. "Any time that you play a U.S.-Canada game you want to be on the right side of it, especially for a USA player."
"That rivalry is always there every single year no matter what tournament you play in," said Canada's captain, Adam Henrique. "There’s always a bit more on the line. It’s a tough loss for us tonight, we have to rebound and put our best foot forward tomorrow."
"Offensively, we wanted to make sure our D was more involved on the back end and from the point," offered American head coach Jack Capuano. "A few of our goals came from there, through traffic, and I thought we did a real good job on that tonight."
Just a few minutes later, though, the Americans opened the scoring after a bad gaffe by Darcy Kuemper at the other end. He was checked by Conor Garland behind his goal while trying to play the puck, and Jason Robertson slid the loose disc into the open net at 9:43.
Canada’s lack of scoring touch was evident just before that goal. Michael Bunting had a great chance with an open net of his own, but a strong stick check by Zac Jones prevented a Canadian goal.
The Americans blew the game open with three more goals in the second, starting with a goal just 1:19 into the period. Adam Clendening’s long shot found its way through traffic and fooled Kuemper, and two minutes later Moore made it 3-0 on a power play when he tipped a pass and then had the tip go off his skate and in.
Canada had plenty of puck possession and good movement, but any time they got a decent scoring chance Oettinger was right there. The dagger came at 18:20 when Jaret Anderson-Dolan mishandled a pass behind his goal. The puck came out to Moore who snuck a shot under Kuemper’s blocker.
Given the score and Kuemper's shaky play, coach Gerard Gallant inserted Adin Hill for the third period. He was solid, but more important Canada finally scored, at 11:35, thanks to a quick shot in front by Maxime Comtois over the shoulder of Oettinger. The play was set up by a great pass from Nicolas Beaudin along the left-wing boards, and the relief on Comtois' face spoke to the relief felt by the whole team.
"We were waiting six periods to score our first goal," Comtois said. "It was an unbelievable play by Nic. We said that in the room in intermission--we have to get that first one and after that we can play looser and we'll get more. It was a big relief."
But if Canada thought it would start a comeback, the U.S. ended that hope with another long-shot goal through traffic, this from Matt Tennyson with just under three minutes remaining.
Canada plays Germany tomorrow night while the United States has a day off before playing Kazakhstan on Tuesday.
"Obviously, this isn't the way we wanted to start the tournament," said Canadian forward Justin Danforth. "I thought there were a lot of positives from yesterday's game. Even the first period today, we played our game. We got away from that in the second, and they capitalized. But we got that first goal out of the way so now we have a tough game tomorrow."