The Brazilian pair topped Pool F by defeating teams from Finland and Slovakia on the first day of main draw action in Espinho.

Freitas and Alves overcame Finland's Riikka Lehtonen and Niina Ahtiainen 22-20, 21-19 and Slovakia's Andrea Strbova and Natalia Dubovcova 21-11, 21-19 to progress to the knockout round amid windy conditions.

"We know there are some things we need to work on some more, especially on our serving, because this wind is making it a little more difficult to serve well," said Freitas.

"But tactically I think we did a good job. 

"In the first game we were adapting to these conditions and I think we are getting better each game and hopefully tomorrow we will play even better."

Greece's Vasiliki Arvaniti, who has become the record appearance holder as this tournament is her 176th major competition, and partner Panagiota Karagkouni were among the other pairs to qualify for the main draw.

Arvaniti and Karagkouni, who came through qualification yesterday and are the lowest-ranked team in the event, edged out Kelly Claes and Sarah Sponcil of the United States 21-17, 13-21, 15-12 before they despatched Poland's Kinga Wojtasik and Katarzyna Kociolek 21-15, 21-16.

Spain’s Liliana Fernandez Steiner and Elsa Baquerizo McMillan produced the upset of the day as they ousted second seeds Barbora Hermannova and Marketa Slukova 21-19, 21-18 to top Pool B.

The men's draw is due to get under way when the event resumes tomorrow.