Team Canada's Jordan Eberle celebrates with John Tavares, front, during his team's comeback win over the U.S. on Wednesday night. ((Adrian Wyld/Canadian Press) )

It's not easy walking the emotional tightrope the Canadian juniors are straddling at the world junior hockey championship.

The Canadians are at their best when they play with an edge — they go hard, finish their checks and keep their emotions in check.

This is how they win.

They are at their worst when they are too high, too primed for prime time — their emotions run amok, discipline goes AWOL, and they dig a deep hole.

That's what happened in the first 10 minutes of the game against the United States a couple of days ago.

It was New Year's Eve in the nation's capital, with Prime Minister Stephen Harper in the stands, with the Americans standing in the way of a free pass to the semifinals and with the weight of four straight world junior championships on their shoulders.

It was a recipe for a perfect storm of emotions, and the Canadian juniors were more than pumped. They were jacked.

After pulling ahead 3-0, the chirping Americans mocked the Canadians as they sat on the bench, and the trash talking backfired.

The Canadian juniors toned down the attitude and cranked up the effort and rallied for a 7-4 win.

After having a constant parade to the penalty box, the Canadians were not penalized over the final 25 minutes and 33 seconds of play, and that says a lot about their commitment to win.

Come Saturday, the Canadians will be back in the same arena, playing a must-win game in front of probably another crowd of 20,000 hockey-mad fans.

Canada faces longtime rival Russia at Scotiabank Place in Ottawa (7:30 p.m. ET).

This collection of Canadian teenagers will be asked again to walk a fine line — to play with an edge but not cross it.

Bar is set high

It seems to be a lot to ask, but it comes with the territory, especially when the bar has been set as high as it is now. This happens when hockey is your national theatre.

How the Canadians will handle the pressure this time will be interesting to watch.

"We can't get too high and we can't get too low and we have to find that middle ground," forward Evander Kane said on Friday after practice. "It is key for us to stay in control."

Cody Hodgson said the players know Canadian fans want nothing but gold, and finding the balance is up to each and every player.

"Some of the penalties [versus the U.S.] were because we were trying too hard. Sometimes we let it get away from us," he said.

"If we are ready, we'll be fine. We learned from that keep to keep our emotions in check and not let the crowd over-hype us."

Team concept hard to find

Saturday's semifinal is only the eighth game the Canadian juniors have played since mid-December when the team was announced.

It's tough to form that elusive team concept that gets such an important moniker in team sports like hockey, but it is something head coach Pat Quinn and his staff work on every day.

Some days it's there, and others it isn't.

"A lot of times you feel comfortable about it but certain players react differently to pressure in certain ways and even though your team building has it all directed on team work and selfishness … in certain stages of the game the other night we saw bonehead plays, gambles, risky stuff," Quinn said.

"It was all of those things that if you talk to those individuals, they will say, 'I will not do that. You can count on me.'

"But throw in the other team and the crowd and the pressure and people make mistakes, decisions not close to what they planned on."

Test comes when pressure mounts

Quinn will have to wait until game time to see whether his players walk the line or cross it, play with fire or maybe have a gold medal dream snuffed out.

"The test is like any athletes that want to have success," he said. "They have to do it when it counts, when it is there and when that pressure is on.

"At this point they are facing more tests."

Hickey was asked whether the players can keep their focus. He nodded.

"The fans will be behind us and we will play like it is our last shift every time out there," he said.

Goaltender chosen

Also Friday, Quinn announced Dustin Tokarski will be back in goal. Tokarski was burned for three early goals against the United States but was strong over the last two periods to earn the start.

"He held steady and got better and showed some control in a panic situation," Quinn said.

Forward Zach Boychuk skated on his ailing ankle and said he'll play in the semifinal.