Men's beach volleyball world champions Alison Cerutti and Emanuel Rego survived a scare before reaching the Olympic semi-finals.
The Brazilian pairing were fought all the way by Mariusz Prudel and Grzegorz Fijalek of Poland before winning 21-17, 16-21, 17-15.
They will next meet Latvians Martins Plavins and Janis Smedins in Tuesday's last four.
But lucky losers Paolo Nicolai and Daniele Lupo saw their run ended.
The Italian pairing, who caused a sensation by in the round of 16, were beaten 21-16, 21-18 by Reinder Nummerdor and Rich Schuil.
The Dutch duo will take on Germans Julius Brink and Jonas Reckermann in the second semi-final.