Top-seeded Timea Bacsinszky of Switzerland beat Anna Blinkova of Russia 6-4, 6-2 to reach the second round of the Grand Prix SAR on Tuesday.
The 15th-ranked Bacsinszky, who broke Blinkova's serve six times, next plays Kateryna Kozlova of Ukraine.
Richel Hogenkamp, a Dutch player ranked 139th, overcame eight double-faults to upset fourth-seeded Irina-Camelia Begu 6-3, 6-4, breaking the Romanian player's serve five times.
She next plays Frenchwoman Pauline Parmentier.
No. 7 Lesia Tsurenko of Ukraine advanced with a 6-4, 6-0 win against Silvia Soler-Espinosa, breaking the Spaniard's serve six times, while No. 8 Yuliya Putintseva of Kazakhstan won 6-3, 7-6 (1) against Alison Riske of the United States, who double-faulted seven times.
Laura Robson, Sara Sorribes Tormo, Tatjana Maria, Aleksandra Krunic and Marina Erakovic also reached the second round.