Sweden opened the Olympic women’s football tournament with a 1-0 win over South Africa ©Getty Images

Sweden opened the Olympic women’s football tournament with a 1-0 win over South Africa in front of vast swathes of empty seats at the 60,000 capacity Estádio Olímpico João Havelange in Rio de Janeiro.

Nilla Fischer scored the only goal of a tense Group E encounter in which chances were at a premium.

Following a scramble in the South African penalty area, the defender was there to poke the ball home in the 76th minute.

A larger, albeit far from capacity crowd, saw hosts Brazil join Sweden at the top of Group E thanks to a 3-0 win over China.

Monica, Andressa Alves and Cristiane all got their names on the scoresheet as Brazil look to go one better than the silver medals they won at Athens 2004 and Beijing 2008.

Local hopes will be pinned on Marta, a five-time Women's World Player of the Year, but who has never won an Olympic gold medal.

The 30-year-old looked sharp against the Chinese but it was her team-mates who scored the all-important goals in a comfortable victory.

In Group F, Canada beat Australia 2-0 despite playing for 70 minutes with 10 players at the Corinthians Arena in São Paulo.

Janine Beckie scored the fastest goal in Olympic women’s football history after just 19 seconds to give Canada the lead.

Shelina Zadorsky was sent off for denying Michelle Heyman a clear goalscoring opportunity, however, Australia were unable to make the most of their numerical advantage.

Canada captain Christine Sinclair put the tie to bed, making it 2-0 in the 78th minute with her 162nd international goal.

Sweden's match against South Africa was played in front of vast swathes of empty seats ©Getty Images
Sweden's match against South Africa was played in front of vast swathes of empty seats ©Getty Images

The other match in Group F, held in the same venue, saw Germany thrash Zimbabwe 6-1.

Goals from Sara Daebritz and Alexandra Popp gave a dominant Germany side a deserved 2-0 lead at half-time.

Kudakwashe Basopo pulled one back for Zimbabwe early in the second-half before a brace from Melanie Behringer put the result beyond doubt.

Melanie Leupolz made it 5-1 in the 83rd minute and the rout was complete when Eunice Chibanda redirected a ball into her own goal.    

In Group G, London 2012 gold medallists the United States claimed a 2-0 victory over New Zealand courtesy of goals from captain Carli Lloyd and Alex Morgan at the Mineirão stadium in Belo Horizonte.

France defeated Colombia 4-0 in the group's other match with Eugénie Le Sommer, Camille Abily and Amel Majri all getting their names on the scoresheet to add to Carolina Arias' early own goal.