Serena advances, Kvitova ousted at U.S. Open

Flushing Meadows, NY ( - Five-time champion Serena Williams was a third-round winner Saturday at the U.S. Open, where another high seed was eliminated.

Williams defeated fellow American Varvara Lepchenko 6-3, 6-3 at Ashe Stadium.

Lepchenko had won only six games total in two previous matches against the world No. 1 star.

Meanwhile, Wimbledon champion Petra Kvitova failed to advance to the fourth round. The third-seeded Czech lost 6-4, 6-4 to Serbian qualifier Aleksandra Krunic.

Kvitova committed six double faults and 34 unforced errors in becoming the fifth top-10 seed to exit in the first week.

Krunic, 21, is making her second main draw appearance at a Grand Slam after losing in the first round of this event last year. She will next face Victoria Azarenka.

Williams will next play Estonia's Kaia Kanepi, who beat 15th-seeded Spaniard Carla Suarez Navarro 7-5, 6-0. Kanepi was a quarterfinalist at this Grand Slam tournament in 2010.

Eugenie Bouchard was able to stave off an upset bid from No. 30 seed Barbora Zahlavova Strycova in Saturday's evening session, with the seventh-seeded rising Canadian rallying in the third set to record a 6-2, 6-7 (2-7), 6-4 decision over the veteran Czech.

The 16th-seeded Azarenka improved to 6-0 lifetime against Elena Vesnina with a 6-1, 6-1 thrashing of the Russian. Azarenka, who lost to Williams in the last two U.S. Open finals, registered her 100th win at a Grand Slam.

Veteran Italian Flavia Pennetta, Russian Ekaterina Makarova and Aussie Casey Dellacqua also reached the round of 16.

The 11th-seeded Pennetta routed American wild card Nicole Gibbs 6-4, 6-0 to set up a meeting with the 29th-seeded Dellacqua, a three-set winner over Czech Karolina Pliskova.

Makarova, the 17th seed, beat Kazakhstan's Zarina Diyas in straight sets to set up a fourth-round matchup with Bouchard.