Top-seeded Nicolas Almagro of Spain beat Rui Machado of Portugal 6-2, 6-4 to reach the Brazil Open semi-finals.
Third-seeded Brazilian Thomaz Bellucci was bounced out 6-2, 6-1 by No. 5 Juan Ignacio Chela. Almagro will face Chela in the semi-finals of the clay court event.
He will be trying to repeat the title he won here in 2008. Almagro is bidding for his eighth ATP title, and seven of them have come on clay.
Alexandr Dolgopolov of Ukraine also advanced on Thursday, beating Italy's Potito Starace 6-3, 6-4.
Standing between the fourth-seeded Dolgopolov and his first ATP final is unseeded Ricardo Mello of Brazil, who routed Pablo Andujar of Spain 6-1, 6-0 to reach the semis for the second straight year.