South America's first Olympic Games kicked off with women's football last night, when Sweden beat South Africa 1-0.

Although the opening ceremony takes place tomorrow (11pm SA time), the football competitions began ahead of time with six women's matches yesterday and another eight men's games today.

The opening action at Rio's Olympic Stadium was lacklustre with a few clear chances.

Nilla Fischer scored Sweden's winner after 75 minutes, bundling the ball into the net with her knee after Banyana Banyana keeper Roxanne Barker failed to hold a cross.

Sweden were superior, particularly in the first half, but could not turn possession into goals.

The result means South Africa have yet to win an Olympic football match in their four finals appearances since their debut at the 2012 Olympics.

But last night's result was no disgrace for Banyana, who lost 4-1 to the same opposition in London four years ago.

Coach Vera Pauw's side will face China at the same venue in their next match on Saturday (at midnight SA time). They will then meet hosts Brazil in their final group match on Wednesday (2am SA time).