Rafa Nadal beat Thomaz Bellucci to reach the last four of the men’s singles in Rio.
The Spaniard, who has been struggling with injury since withdrawing from the French Open in May, came back from a set down to win 2-6 6-4 6-3 against the local favourite.
Nadal will take on either Argentina's Juan Martin del Potro or Spain's Roberto Bautista Agut in the semi-finals.
Nadal turned away by restaurant says Hoy
The Spaniard will also compete for a gold medal in the men's doubles final later Friday, where he is teamed with compatriot Marc Lopez against a duo from Romania, Florin Mergea and Horia Tecau.
In the first women's singles semi-final of the Games, Puerto Rico's Monica Puig beat Petra Kvitova of the Czech Republic for a spot in the gold-medal match.
Monica Puig (PUR) of Puerto Rico celebrates after winning her match against Petra Kvitova (CZE) of Czech Republic.
Image credit: Reuters
Puig, ranked 34 in the world, won a decisive third set to go through 6-4 1-6 6-3. She will compete in the final for what may be her country's first medal of the Games, and its first ever gold.
"It would be unbelievable and it would be the biggest honour in the world," Puig said on the prospect of winning gold.
The island is full of such bad news all the time, so every time there's a Games and somebody from the island wins a medal everything stops and I know how happy people get.
Island nation Puerto Rico, which has been facing a deep financial crisis, has captured a total of just eight medals at past Games, mostly in boxing.
Puig will take on either American Madison Keys or Angelique Kerber of Germany in the final.
The Olympic tennis tournament has been marked by upsets with both the men's and women's top seeds, Serbia's Novak Djokovic and American Serena Williams, knocked out in the early rounds.
Murray corrects Inverdale over gender error to earn Sturgeon praise
Majestic Andy Murray completes ‘Super Sunday’