World number five Kei Nishikori was sent crashing out of the Rio Open by Brazil’s Thomaz Bellucci in the first round.
The top seed went down 6-4 6-3 on the clay, having his serve broken four times by Bellucci.
Nishikori’s exit opens things up nicely for second seed Dominic Thiem, who progressed past Janko Tipsarevic 6-4 7-5.
Champion in 2015 David Ferrer is out, though, as he lost 6-4 6-4 to Alexandr Dolgopolov of the Ukraine while Italian Paolo Lorenzi was another seed to fall, losing to Federico Delbonis 4-6 6-1 6-4.
No.4 seed Pablo Carreno Busta defeated Joao Souza 6-3 6-2 while No.5 seed Albert Ramos-Vinolas rolled over Stephane Robert 6-2 6-0.
There were also victories for Fabio Fognini, Thiago Monteiro, Victor Estrella Burgos and Horacio Zeballos.