The Rio 2016 Olympic Games began  with a women's football match played in front of a sparse Olympic Stadium crowd.

Sweden won 1-0 against South Africa in the opener, before host nation Brazil beat China 3-0.

Plenty of empty seats could be seen in the 60,000 venue at kick-off, although more fans arrived before Brazil's game.

The football tournament has started two days before Friday's opening ceremony because of a packed schedule.

More than 11,000 athletes will compete in the first edition of the Olympic Games to be held in South America.

There are 42 Olympic sport disciplines, with 306 events over the course of 19 days of competition.

Football is the only sport that will be staged at venues across the country.

Sweden, who are ranked sixth in the world, secured the first win of the tournament when Nilla Fischer bundled in a second-half goal after a goalkeeping mistake.

Brazil, who lost at the quarter-final stage of the London 2012 Games, were comfortable winners with goals from Monica, Andressa Alves and Cristiane.

Striker Marta - who did not add to her 102 goals in 104 caps - said: "Scoring three times against a team like China, with all the pressure we had, I think it's super-perfect."

Canada's Janine Beckie scored after just 20 seconds against Australia, the fastest goal in Olympic women's football history, as they won 2-0 at the Corinthians Arena in Sao Paolo.

Canada score in opening 20 seconds against Australia

Germany, who finished third in 2000, 2004 and 2008, had no problems against Zimbabwe in their opening game, winning 6-1. At one point it was 2-1 but the African side tired towards the end of the match, conceding three goals in the final 16 minutes.

The USA, who are attempting to win a fourth consecutive Olympic gold medal, started their campaign with a 2-0 win over debutants New Zealand.

Fifa women's player of the year Carli Lloyd and Alex Morgan scored in each half at Mineirao stadium in Minas Gerais, as the US retained their unbeaten record in 2016.

In the final match of the day, France cruised past Colombia 4-0. An own goal from Carolina Arias opened the scoring, followed by a header from Eugenie Le Sommer, and free-kicks from Camille Abily and Amel Majri.

The men's competition, which is contested by under-23 teams, starts on Thursday.