Holders Switzerland won both of their matches on the opening day of the World Women's Curling Championship, beating the US and Japan ©Getty Images

Defending champions Switzerland won both their matches on the opening day of the World Women’s Curling Championship in Sandviken, Sweden.

Switzerland, who are seeking a fourth world women’s title in the space of five years, edged past the United States in the first session of round-robin matches at the Goransson Arena.

Despite not scoring more than a single shot in any end, Switzerland triumphed 7-5 with singles in ends nine and ten the crucial scores, after the US had levelled the contest at 5-5 with a score of three in end seven.

In their second match of the day, the Switzerland team, skipped by Silvana Tirinzoni, ran out comfortable 11-2 winners over Japan, with a score of six on the second end, proving too big a blow for their opponents to recover from.

Hosts Sweden also played twice on the opening day, with the team skipped by Anna Hasselborg starting off with a devastating display.

The Swedes beat New Zealand 14-2 in the opening session, with a score of six on the fourth end coming following two scores of three on ends one and three.

In the second session, the hosts were beaten 9-4 by Canada, who scored four on the final end to earn a victory that was not as comfortable as the result suggested.

The opening session of play featured two more tight contests, with Norway beating South Korea 8-6 and Denmark defeating Japan 7-6, scoring a crucial single in the last end to break the deadlock.

Meanwhile in the second session Scotland started their campaign with a 12-5 win over Germany, while Italy were big winners over Turkey by a 12-1 margin.

A total of 20 round-robin sessions are scheduled over the next seven days, with the top six ranked teams advancing to the knockout stages.