Chelsea Carey is going to sleep off her first loss at the world women's curling championship.

The Canadian skip dropped a 6-3 decision to Russia's Anna Sidorova on Monday morning in Draw 6 action at the Credit Union iPlex. Carey missed shots in the seventh, eighth and ninth ends as the win slipped from her grasp.

"I just need to go get some sleep," said Carey, who planned to nap before facing Sweden's Margaretha Sigfridsson in the evening. "I just didn't sleep last night and I wasn't in a great headspace and I fought hard to get there and I just couldn't get it together."

Russia (3-1) used a conservative style in the early going and capitalized on a missed takeout by Canada (3-1) in the seventh end for a decisive two points. Sidorova, with the hammer, threw an easy draw for two and a 4-3 lead.

"I missed one shot and that really turned the tables," said Carey. "If I make that shot it totally changes the momentum of the game. We weren't able to recover."

Canada was too light on its attempt at a tap in the eighth end, giving Russia another point.

The struggles continued for Carey in the ninth end as she failed on an attempted triple takeout. Instead, Russia stole a point to make it 6-3 heading to the final end.

Sidorova kept the house clear in the 10th end, with the Canadians shaking hands with a stone still to throw.

"I was really tired this morning, which didn't help anything," said Carey. "That's not necessarily enough to cause you to lose.

"It's not so much frustrating that we lost, it's that we handed it to them."

Carey's Calgary-based rink was the last undefeated team at the tournament as Japan (3-1) was upset by Denmark (2-2) earlier in the same draw.

Sidorova is a two-time European champion and has won bronze twice at the world championships while Carey is making her debut at this event. Canada hasn't won world women's gold since 2008.

"We're happy to win against Canada because you guys have the greatest team in the world," said Sidorova. "This is a big win for us. But it means nothing, as we still have lots of games to play."

Russia opened with a hit and roll for a deuce in the first end, followed by a scoreless second. Carey took a 3-2 lead in the third end with a smooth tapout for the triple.

Sidorova continued her conservative play in the fourth, going for the blank to keep it a one-point game. She did the same in the fifth and sixth ends to keep the hammer.