Dominic Thiem and Albert Ramos-Vinolas reached the Rio Open quarter-finals with straight-sets wins on Wednesday.
Thiem, the talented Austrian and second seed, outclassed Serbia's Dusan Lajovic 6-2 7-5 on the clay courts in Brazil.
The world number eight broke serve three times on his way to the last eight at the ATP 500 event.
Thiem enjoyed a tremendous 2016, particularly on clay - a surface on which he held a 25-7 win-loss record.
Awaiting him in the quarter-finals is Diego Schwartzman, who won an all-Argentine affair against Federico Delbonis 6-4 7-6 (7-1).
The fifth-seeded Ramos-Vinolas was even more comfortable, easing past Italian 2015 runner-up Fabio Fognini 6-2 6-3.
The Spaniard will next face Nicolas Kicker after the Argentinian beat fellow qualifier Arthur De Greef 6-3 6-3.
Belgian De Greef had caused a huge shock in the opening round with a win over defending champion Pablo Cuevas.