HAMEENLINNA, Finland — Julie Chu and Hilary Knight scored three goals each as defending champion United States routed Japan 8-0 Saturday at the World Hockey Championships.

The Americans outshot Japan 74-8 in their opening game.

"It was a good way to start things off," said U.S. coach Mark Johnson. "From an offensive standpoint, we generated a lot of scoring opportunities. Everybody got their feet wet and now we can continue to move forward in the tournament."

Japan didn't manage a single shot in the first period, as the U.S. took a 4-0 lead after accumulating 29 shots, including two goals on power-plays and one short-handed. Jenny Potter had two assists in the period to reach her career 100th assist for the United States.

Megan Van Beusekom earned her first shutout with eight saves.

The Americans close out preliminary-round play in group A on Monday against Russia.

In group B, Canada crushed China 13-1. Rebecca Johnston, Hayley Wickenheiser, Gillian Apps and Sarah Vaillancourt led the scoring with two apiece.

Wickenheiser, who also had three assists, said she hoped the difference in skill level between the best and worst teams would decrease in the next few years.

"An outsider who has never watched the game is going to say 'What is that?'" said Wickenheiser, the Canadian captain. "The reality is, is China going to be a top-five team at an Olympic Games? I don't think so, but you've got to look to what's out there: Finland, Sweden, the U.S. and Canada, maybe the Swiss or maybe Russia.

"Those are the games that are really going to elevate the sport. There's nothing you can do about it, but show the discipline and skills that we have."

Long considered the best player in women's hockey, Wickenheiser has played in three Olympics and eight world championships. She did not play in the 2001 worlds because of a knee injury.

This season, she played in Sweden for Eskilstuna, in the third tier of Swedish men's pro hockey.

Canada goaltender Charline Labonte faced only four shots.

Canada next meets Sweden on Monday. Sweden, which finished second behind Canada at the 2006 Turin Olympics, beat the Canadians for the first time 3-2 in overtime at the Four Nations Cup in November at Lake Placid, N.Y.

The nine-time champion Canadians are attempting to reclaim the world title they lost to the U.S. last year in Harbin, China.

Host Finland shut out Kazakhstan 7-0 in group C, which also includes Switzerland.