American Jack Sock lost 7-5, 6-1 to unseeded Federico Delbonis in the first round of the Rio Open on Monday. The No. 6 seed, Sock lost in just one hour and 17 minutes.
No. 8 seed Thomaz Bellucci was also an upset victim, with the Brazilian falling in his home country to Alexandr Dolgopolove, 6-7(3), 7-5, 6-2.
No. 2 seed David Ferrer, No. 3 seed Dominic Thiem and No. 7 seed Fabio Fognini were straight sets winners.
In the women's draw, Brazil's Teliana Pereira entered as the top seed, but was upset by Petra Martic 6-3, 7-5. No. 2 seed Johanna Larsson and No. 6 seed Lara Arruabarrena were straights sets winners.
OPEN 13 PROVENCE
No. 5 seed Gilles Simon was upset by Teymuraz Gabashvili, 3-6, 6-3, 7-6(7) in the first round of the Open 13 Provence in Marseille. Simon was the only seed in action Tuesday.
Australian Nick Kyrgios was a straight sets winner over Canadian Vasek Pospisil, 6-4, 6-4.