The Japanese side inflicted a 6-5 defeat on the reigning Olympic gold medallists at the Ralston Arena.

Sweden have won their past five competitions in a row, including the European Championships. 

Japan seem to be a weakness for the Swedish side, however, with their last defeat occurring against the Japanese team in the first leg of the World Cup in Suzhou.

“I’m really so happy because it’s a big game and Sweden is a very good team,“ said Japan’s vice-skip Chinami Yoshida. 

“We have many games against them so we know their plans and are comfortable. 

"We are confident about the ice and happy about the result.”

Scotland beat China in the other Group B match to be held on the opening day of the tournament.

In Group A, Canada secured a 7-5 victory over Russia, while the United States defeated South Korea 9-5. 

There was another shock defeat in the men's session as China narrowly beat Olympic champions the United States 4-3. 

Scotland built on their maiden win at the European Championships to overcome Canada 8-6 in the other Group A fixture.

Norway comfortably won against Switzerland 10-4 and Sweden defeated Japan 7-4 in Group B. 

In the mixed doubles, Switzerland's Jenny Perret and Martin Rios won a one-stone shoot-out to record a 6-5 victory over Canada in Group A, while South Korea beat Sweden 9-2. 

The United States won 9-6 against Norway and Russia defeated China 8-5 in Group B. 

Tomorrow will see the continuation of the round robin competition in the men's, women's and mixed doubles sessions.