NEW HAVEN, Conn., Aug. 20 (UPI) --
Defending champ Petra Kvitova
rallied for a victory but second-seeded Angelique Kerber
fell in an upset Tuesday in second-round play at the New Haven Open.
Kvitova, seeded third, dropped the first set against German lucky loser Annika Beck 4-6, but then bounced back to win the next two sets 6-3, 6-3.
The Czech Republic native goes on to face American qualifier Alison Riske in the quarterfinals.
Kerber, however, wasn't as fortunate, succumbing to 2009 runner-up Elena Vesnina of Russia 6-2, 6-4 at the Yale University hard courts.
Also falling in an upset was No. 7 German Sabine Lisicki. Last month's Wimbledon runner-up was surprised by Russia's Anastasia Pavlyuchenkova 7-5, 6-3.
Meanwhile, Czech Klara Zakopalova bested Puerto Rican qualifier Monica Puig 6-4, 6-1. She'll next face Vesnina in the quarters of the U.S. Open tuneup.
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