Brazilian favorites Emanuel Rego and Alison Cerutti moved into the quarterfinals of the men's beach volleyball tournament with a straight-set win Saturday.
Later, the American teams of Misty May-Treanor and Kerri Walsh Jennings and Jake Gibb and Sean Rosenthal were playing late matches at Horse Guards Parade.
Rego, a 2004 gold medalist, and Cerutti needed just 38 minutes to knock off Germany's Jonathan Erdmann and Kay Matysik 21-16, 21-14.
Reinder Nummerdor and Rich Schuil of the Netherlands also moved into the quarters on the men's side with a 22-20, 21-15 win over Patrick Heuscher and Jefferson Bellaguarda of Switzerland.
On the women's side, China's Zhang Xi and Xue Chen beat Russia's Ekaterina Khomyakova and Evgeniya Ukolova 21-12, 21-11; and Greta Cicolari and Marta Menegatti of Italy topped Liliana Fernandez Steiner and Elsa Baquerizo of Spain 21-15, 21-15.
May-Treanor and Walsh Jennings, the two-time reigning Olympic champions, will play Marleen van Iersel and Sanne Keizer of the Netherlands.
Gibb and Rosenthal will play Russians Sergey Prokopyev and Konstantin Semenov.