The Americans, ranked No. 1 in the world and the favourites to win gold in Tokyo, were riding a 44-match unbeaten streak heading into Wednesday's match.

Sweden, ranked No.5 and who also bounced the Americans from the 2016 Rio de Janeiro Games in the quarter-finals, took a first-half lead when Blackstenius' header found the net.

Blackstenius scored again in the 54th minute, beating goalkeeper Alyssa Naeher, as the Americans continued to struggle. Lina Hurtig then scored in the 72nd.

The loss was the first for the United States under Andonovski, who took over when former coach Jill Ellis stepped down following the team's World Cup victory in France.

The Swedes were without Magda Eriksson because of injury. The team said she has been training, but because of the compact schedule of the tournament she was held out of the opener.

Tokyo is Sweden's seventh Olympics while the United States have four Olympic gold medals, more than any other nation.

The United States next face New Zealand while Sweden meet Australia on Saturday.

Marta earlier became the first player to score in five straight Olympics in Brazil's 5-0 win over China.

Marta finished with a pair of goals for Brazil, who are ranked No. 7 in the world. Debinha, Andressa Alves and Beatriz also scored.

A six-time FIFA Player of the Year, Marta has 111 international goals, more than any Brazilian player, male or female. After her goal in the ninth minute, Debinha added another in the 22nd to put Brazil up 2-0.

Marta added her second goal in the 74th minute before Alves scored from the penalty spot. Beatriz closed out the rout with a goal in the 89th.

Brazil are playing intheir first major tournament under Pia Sundhage, the former coach of both the US and Swedish women teams. Sundhage coached the US team to the gold medal at the 2012 London Games.

In other matches Britain beat Chile 2-0 at the Sapporo Dome with Manchester City forward Ellen White scoring twice.

Hosts Japan and Canada drew 1-1, with Mana Iwabuchi netting the equaliser in the 84th minute to salvage a point.

Christine Sinclair, the all-time leading international scorer among men and women, scored her 187th career goal in the sixth minute to give the Canadians the early lead. It came in her 300th appearance with the team.

Vivianne Miedema scored four goals as the Netherlands routed Zambia 10-3.

Miedema, the all-time leading scorer in the Women's Super League, as well as the top career scorer for the Netherlands, had goals in the ninth, 15th, 29th and 59th minutes.

Australian Associated Press