Lucie Safarova recorded a straight sets win over Johanna Larsson to ease into the second round of the Family Circle Cup in Charleston on Monday.
The Czech ninth seed progressed thanks to a straightforward 6-2 6-3 victory against the 25-year-old from Sweden.
Safarova will next meet Frenchwoman Virginie Razzano in the next round after she defeated Germany's Julia Goerges 6-0 5-7 6-2.
The shock of the opening round saw Swiss qualifier Belinda Bencic dump out 10th seed Maria Kirilenko 6-1 7-5.
Top seed Serena Williams was given a bye in the first round but she will face Slovakia's Jana Cepelova in round two after she beat American Melanie Oudin 7-6 (7/2) 6-2.
Hard-hitting American Madison Keys came through two tie-breaks to win 7-6 (7/0) 7-6 (7/3) against Mirjana Lucic-Baroni.
South Africa's Chanelle Scheepers beat Alison Riske while qualifier Alla Kudryavtseva defeated Christina McHale and Lauren Davis saw off the challenge of Dinah Pfizenmaier.
There were also wins in the first round for Petra Cetkovska, Kiki Bertens, Teliana Pereira, Yaroslava Shvedova, Ajla Tomljanovic, Elina Svitolina and Grace Min.