Sara Errani became the highest-seeded loser to this point at the 2013 U.S. Open.
Flavia Pennetta sent her fourth-seeded fellow Italian packing, 6-3, 6-1, in second-round action Thursday at the USTA Billie Jean King National Tennis Center. The 31-year-old Pennetta reached three U.S. Open quarterfinals from 2008-11 before missing last year's edition of her best Grand Slam event due to a right wrist injury.
The 26-year-old Errani was the French Open runner-up and a U.S. Open semifinalist last year.
Meanwhile, eighth-seeded German left-hander Angelique Kerber held off promising Canadian Eugenie Bouchard, 6-4, 2-6, 6-3, resurgent Serb Jelena Jankovic, seeded ninth at this fortnight, whipped Russian Alisa Kleybanova, 6-3, 6-2, and 10th-seeded Italian Roberta Vinci overcame Czech Lucie Safarova, 4-6, 6-1, 6-2. The 24-year-old Kleybanova returned to the WTA earlier this month after battling Hodgkin's lymphoma, a form of cancer, over the last two years.
The French Open quarterfinalist Jankovic is a former world No. 1 who lost to Serena Williams in the 2008 U.S. Open finale.
Wimbledon runner-up Sabine Lisicki, seeded 16th in Flushing, drilled Argentine Paula Ormaechea, 6-2, 6-3.
In other second-round action involving seeds, Japan's Kurumi Nara surprised No. 19 Romanian Sorana Cirstea 7-5, 6-1; No. 24 Russian Ekaterina Makarova doused American Bethanie Mattek-Sands 6-4, 6-4; No. 25 Estonian Kaia Kanepi dismissed Slovak Anna Schmiedlova 6-4, 6-1; and No. 27 Russian Svetlana Kuznetsova held off Chinese Peng Shuai 6-1, 4-6, 6-4. The former top-five star Kuznetsova captured the U.S. Open title in 2004 and was the runner-up in New York in 2007.
Additionally, American Christina McHale bested Ukrainian Elina Svitolina 6-4, 3-6, 7-5 and Kazakhstan's Yaroslava Shvedova handled Austrian Patricia Mayr- Achleitner 6-2, 6-3.