April Ross and Jennifer Kessy claimed a surprise win over Brazil to set up an all-American final in the women's beach volleyball tournament.
Ross and Kessy beat top seeds and reigning world champions Juliana Silva and Larissa Frana 15-21 21-19 15-12.
Earlier, defending two-time champions Misty May-Treanor and Kerri Walsh Jennings beat China's Xue Chen and Zhang Xi 22-20 22-20.
In the men's final, top seeds Brazil will meet Germany.
The Brazilian pair of Alison Cerutti and Emanuel Rego, the reigning men's world champions, beat Martins Plavins and Janis Smedins 21-15 22-20 to ensure a third straight medal for Cerutti, but a first for Rego.
They will meet the German team of Julius Brink and Jonas Reckermann, who beat Reinder Nummerdor and Rich Schuil of the Netherlands 21-14 21-16, in the final.