ST. PETERSBURG, Russia — Brendan Gallagher and Brad Marchand are used to getting under each other's skin. Now they are deploying their abrasive playing styles in pursuit of a common goal.

Gallagher, a scrappy forward with the Montreal Canadiens, and Marchand, an agitator with the rival Boston Bruins, each had a goal as Canada kicked of its defence of its world hockey championship title with a 5-1 rout of the United States on Friday.

"I told him it was too bad — I enjoyed hating him all these years," Gallagher jokingly said of Marchand. "He's a good guy. He plays hard, he competes. Definitely nice to have him on the team."

Taylor Hall, Matt Duchene and Boone Jenner also scored for Canada, who won the world championship last year with a more veteran squad led by superstar Sidney Crosby.

"It's a younger group and it's a passionate group," coach Bill Peters said. "They love to play. They're hungry to be on the ice and want to be great and want to achieve something here."

Cam Talbot made 24 saves and kept the Canadians in the game with strong goaltending, particularly when the Americans surged early in the second period.

Patrick Maroon opened the scoring for the Americans with a first-period power-play goal, and Keith Kinkaid made 28 saves.

This year's world championship presents an opportunity for players who were left off preliminary rosters for September's World Cup of Hockey to make their cases for inclusion when each team's final seven names are announced on June 1.

All of Canada's goal-scorers have solid pedigrees and are making an effort to impress national team brass, although the players insist they're keeping their focus on repeating as world champions.

"Our only goal is to win a championship," Gallagher said. "I think whatever happens, happens, but we use this opportunity for what it is. Just get out there and enjoy competing with this group of guys. Very talented team and we're all enjoying being here."

Hall and Duchene were both members of the Canadian world championship squad last year in Prague, while Gallagher and Jenner were part of the bronze medal-winning world junior team in 2012. Marchand is a two-time world junior gold-medallist.

The game also provided a preview of a matchup that could dominate NHL headlines in years to come. St. Petersburg's 6,000-seat Yubileiny Arena was filled near capacity to watch Canada's Connor McDavid, the first pick at the 2015 NHL draft, go head-to-head against U.S. centre Auston Matthews, projected to be chosen first by the Toronto Maple Leafs in June.

Neither player got on the scoresheet as sparks failed to fly in the anticipated matchup. Neither player had a point and Matthews was held to three shots on goal and had a minus-1 defensive rating, while McDavid failed to register a shot.

Matthews spent the 2015-16 season playing with the Zurich Lions of the Swiss League, and many of his opponents were seeing him for the first time.

"He's a big guy," acknowledged McDavid of the six-foot-two, 194-pound 19-year old. "He's hard on the puck, good on draws and all that. He's a good player."

After leaving the game in the first period with an apparent shoulder injury, American defenceman Jake McCabe returned to action midway through the game.

Later in St. Petersburg, Finland downed Belarus behind two goals and an assist from top draft prospect Patrik Laine.

In the tournament's other bracket in Moscow, Sweden defeated Latvia 2-1 in overtime and the Czech Republic shocked host Russia 3-0.

Canada will next face Hungary on Sunday, while the Americans return to action on Saturday against Belarus.