Brazil's women footballers ensured the opening day of action at Rio 2016 was a happy one for the hosts with a 3-0 win over China on Wednesday.

Rio de Janeiro: Brazil's women footballers ensured the opening day of action at Rio 2016 was a happy one for the hosts with a 3-0 win over China on Wednesday.

The sight of vast swathes of empty seats at the 60,000-seater Olympic stadium for Sweden's 1-0 win over South Africa in the first match of the Games will have embarrassed organisers.

A healthier, albeit far from capacity crowd enjoyed the Canarinhas victory as goals from Monica, Andressa Alves and Cristiane eased Brazil to a comfortable win.

Expectations are high that five-time World Player of the Year Marta can inspire Brazil to go one better than the silver medals they won at the 2004 and 2008 Games to end the USA's run of three straight golds.

The 30-year-old, playing in her fourth Olympics, showed flashes of brilliance in the first-half, but it was Cristiane who was most dangerous early on as she looked to add to her record 12 goals in Olympic competition.

Cristiane's first effort was brilliantly saved by Zhao Lina in the Chinese goal before another goalbound shot was cleared off the line by Tan Ruyin.

The opener finally came in bizarre fashion when Monica's tame header trickled past a sea of Chinese defenders and Zhao into the bottom corner.

Marta then showed her class by creating the second on the hour mark as she skipped down the right before picking out Andressa Alves for a volleyed finish.

China's eccentric French coach Bruno Bini claimed in the build-up to the game that the Chinese women "work harder and they complain much less" than the French side he led to the 2011 World Cup semi-finals.

Whilst there was no lack of effort, China lacked the quality in attack to muster a fightback.

Only a stunning save from Zhao prevented Marta sealing the win in style after a fine solo run and shot that was arrowing towards the bottom corner.

Marta was then replaced to a rousing reception before Cristiane nipped in ahead of Zhao to head home the third.

Sweden beat South Africa

Sweden's women claimed the first victory of the tournament 1-0 over South Africa in an underwhelming start to the Games earlier on Wednesday.

Nilla Fischer bundled home after South African goalkeeper Roxanne Barker fumbled a cross for the only goal of the game.

"It is a great feeling to have a big crowd, but today for us it was only about football, winning 1-0, and moving forward," said Sweden coach Pia Sundhage in response to the paltry attendance.

"We didn't play the way we should have and we didn't play well but I am very satisfied with the result."

Hundreds of thousands of football tickets remain unsold for both the men's and women's football tournaments that are being staged in six cities across Brazil that also hosted the 2014 World Cup.

World champions the United States begin their campaign later in Belo Horizonte against New Zealand before Colombia and France also face off in Group G.

Canada beat Australia 2-0 in a battle between two quarter-finalists from last year's World Cup despite playing 70 minutes with 10 men to top Group F.

Janine Beckie gave the Canadians an incredible start with the fastest goal in women's Olympic history after just 19 seconds.

Shelina Zadorsky was then sent off for denying Michelle Heyman a clear goalscoring opportunity.

Australia missed a host of chances to make their numerical superiority count, whilst Beckie also saw a penalty saved for Canada.

However, Canada's veteran captain Christine Sinclair made it 2-0 with her 162nd international goal from fully 40 yards after rounding Aussie 'keeper Lydia Williams.

Two-time world champions Germany are expected to ease past Zimbabwe in the other game in the group later in Sao Paulo.