RIO DE JANEIRO (AP) -- Third-seeded Danka Kovinic of Montenegro and No. 5 Polona Hercog of Slovenia each advanced to the second round with wins over Americans at the Rio Open clay-court tournament on Monday.
Shelby Rogers had an upset 6-2, 6-2 win over No. 8 Andreea Mitu of Romania.
The combined ATP and WTA tournament was halted by torrential evening rain that pushed back play by several hours.
In the only men's match completed, Guido Pella of Argentina upset No. 4-seeded John Isner 7-6 (5), 5-7, 7-6 (8).
Rafael Nadal is seeded No. 1 and David Ferrer is No. 2. Teliana Pereira of Brazil is seeded No. 1 for the women and Johanna Larsson of Sweden is No. 2. None of the top seeds were to play Monday.
Nadal faces fellow Spaniard Pablo Carreno Busta on Tuesday and Ferrer plays Nicolas Jarry.