Top-seeded Shahar Peer defeated Japanese qualifier Ryoko Duda 6-4, 6-2 to advance to the second round of the inaugural WTA Citi Open.
Peer became the highest ranked women's tennis player from Israel earlier this year, but came to College Park having lost four straight first-round matches.
Second-seeded Nadia Petrova of Russia downed qualifier Alexandra Mueller 6-2, 6-2 in the American's first career WTA main draw match. Petrova will next face Canada's Eugenie Bouchard, who defeated American Alison Riske 6-3, 6-2.
China's Shuai Zhang upset fourth-seeded Jelena Dokic of Australia 6-3, 6-4. Dokic had 16 double faults in the loss.
Eighth-seeded Alberta Brianti of Italy ousted Britain's Anne Keothavong 6-3, 6-4. American Madison Brengle advanced to the second round as a qualifier by defeating Melinda Czink of Hungary 7-6 (5), 7-5. Irina Falconi of the United States eased past Belarus' Olga Govortsova 6-3, 6-4.
American Jill Craybas, the oldest player in the field at age 37 advanced over China's Jie Zheng 2-6, 6-3, 6-2; fifth-seeded Bojana Jovanovski of Serbia defeated Slovakia's Petra Rampre 6-0, 6-2; and Russia's Alla Kudryavtseva beat South African Chanelle Scheepers 4-6, 6-4, 6-2.