ESPOO, Finland — Natalie Spooner's hat trick helped Canada rumble Russia 5-1 at the women's world hockey championship Monday, but the victory was costly.

Captain Marie-Philip Poulin reinjured her left knee late in the first period. She limped to the dressing room and is not expected to play Tuesday against Finland.

Poulin hurt her knee Feb. 24 playing for Les Canadiennes de Montreal in the final game of the Canadian Women's Hockey League's regular season.

Poulin participated in warmup and remained on the bench supporting her teammates in Canada's first two games of the world championship.

The captain looked strong and fast in her first shifts Monday, but her return was short-lived.

Her knee buckled when she went into the boards with Olga Sosina late in the first period.

"If you can't continue in the game, that's never a good sign," Canadian head coach Perry Pearn said.

"I'm disappointed for her. She's a great competitor. She's worked really hard to get herself in a position to be able to play. To have her first game cut short is disappointing. Obviously we'll see where it takes us."

Spooner haunted Russia's net, scoring a pair of wraparound goals and also a tip-in to surpass the career 50-goal mark wearing the Maple Leaf.

"They wanted me to be around the net for sure on the power play and I was just kind of finding my way, getting used to being there and I'm enjoying it," Spooner said.

"I can bang in some rebounds and tip some pucks, so it's going great."

Spooner posted a four-point night, also assisting on a Blayre Turnbull goal. Rebecca Johnston also scored for the Canadians, who stayed even with Finland with both at 2-1 in Group A.

Defending champion United States was assured first place in the pool at 3-0.

Canadian goalie Genevieve Lacasse made seven saves for the win in her first start of the tournament.

Russian defender Liana Ganeyeva foiled her shutout bid, scoring a power-play goal early in the third period.

Pearn, meanwhile, said he felt confident prior to the game that Poulin was ready to play.

"She's my linemate so to have her back was awesome," Johnston said. "I love playing with her and for the team, great to have our captain back.

"To not have her finish is definitely disappointing, but she has to get better and hopefully she's feeling good and ready to go later in the tournament."

Canada and the host Finns meet Tuesday to determine second place in Group A.

The Americans conclude the preliminary round against Russia (1-2). Switzerland was 0-4 in the group.

The top five countries in the IIHF's women's world rankings comprise Group A, while six to 10 make up Group B.

All Group A countries and the top three from Group B will play in Thursday's quarterfinals. Saturday's semifinals are followed by Sunday's medal games.

The Czech Republic topped Group B at 3-0. Germany was second with six points, ahead of Sweden with four points, Japan with three and France with two.

Anna Shokhina returned to Russia's lineup after serving a two-game suspension for a kicking infraction at the buzzer of last year's Olympic bronze-medal game in Pyeongchang, South Korea.

Captain Anna Shibanova was barred from last year's Olympic Games by the International Olympic Committee because of a doping rules violation.

The Russians ferociously blocked shots in the first period and held Canada to a single goal in it.

Canada put 45 shots on their net. Goalie Anna Prugova was pulled after Turnbull's goal at 6:22 of the second period for Nadezhda Morozova.

"We played well the first period. We tried our best to be good on defence," said forward Alexandra Vafina, a University of Calgary Dinos alumnus.

"The second period, we got tired and that's why we took so many penalties and got scored (on). The third period was great. We won it."

"We have some points where we have the puck in the offensive zone and we're not shooting a lot. We need to work on that, shooting and go to the net and take a rebound if we have it."

Finland beat Canada for the first time in the preliminary round of the 2017 world championship in Plymouth, Mich., by a score of 4-3.

"We have a lot of players who were (playing) then, but we also have the young ones here who have already proven they are not scared to play against them, so we have a group that's really confident," Finnish assistant captain Michelle Karvinen said.

"You'll see us battling."