They stayed unbeaten by defeating Latvians Tina Graudina and Anastasija Kravcenoka 21-19, 21-13.

Also topping their pool without a loss was Dutch world number ones Katja Stam and Raïsa Schoon having beaten Ana Gallay and Fernanda Pereyra of Argentina 22-20, 21-10.

Olympic silver medallists Taliqua Clancy and Mariafe Artacho del Solar of Australia claimed their second win from two matches by beating Cubans Lidianny Echeverria Benitez and Leila Consuelo Martinez Ortega 21-16, 21-18.

Brazilians Duda and Ana Patricia won 21-12, 21-19 against Czech Republic's Barbora Hermannová and Martina Williams, while defending world champions Canadians Sarah Pavan and Melissa Humana-Paredes claimed a narrow victory over France's Lézana Placette and Alexia Richard 22-20, 21-19.

However, Brazilian world number two Barbara Seixas de Freitas and Carolina Solberg Salgado were upset in their third match against Canadian twins Megan and Nicole McNamara, losing the crucial set with the score finishing 16-21, 21-19, 15-13.

Olympic men's gold medallists Anders Mol and Christian Sørum of Norway continued their form from yesterday with a 21-10, 21-17 victory against Dutch players Leon Luini and Ruben Penninga.

Austrians Martin Ermacora and Moritz Pristauz came from a set down to go top of Pool G by a score of 19-21, 21-19, 15-13, while Brazilians Alison Cerutti and Guto won 21-17, 21-9 against El Salvador's Ruben Alejandro Mora and Miguel Angel Lopez.

The big shock on the men's side of the competition was Australian world number seven pairing Christopher McHugh and Paul Burnett losing to Hans Hannibal and Marco Cairus of Uruguay 21-19, 15-21, 15-13.