Three-time champion Serena Williams round winner Thursday at the U.S. Open.

The 28th-seeded former world No. 1 star flattened Dutchwoman Michaella Krajicek 6-0, 6-1 in a mere 49 minutes at Arthur Ashe Stadium. The 13-time Grand Slam champ closed out the uneventful affair with her 10th ace on a breezy afternoon in Flushing.

Krajicek is the half-sister of former men's Wimbledon champion Richard Krajicek.

The 29-year-old Williams is now riding a 14-match overall winning streak, all on hardcourts, which includes a pair of titles.

Williams will meet the Victoria Azarenka-Gisela Dulko victor in the round of 32.

Seventh-seeded gritty Italian Francesca Schiavone rolled into the third round with a 6-1, 6-1 pasting of Croat Mirjana Lucic, while 10th-seeded rising German Andrea Petkovic overcame diminutive Chinese Zheng Jie 3-6, 6-3, 6-3. The 31-year-old Schiavone was this year's French Open runner-up and last year's French Open champ.

Up next for Schiavone will be South African Chanelle Scheepers.

Former U.S. Open runner-up Jelena Jankovic advanced on Day 4 of the fortnight with a 6-3, 6-4 handling of former top-10 player Jelena Dokic of Australia. The former world No. 1 Jankovic, of Serbia, was the 2008 U.S. Open runner-up to Williams.

Jankovic has been nursing a sore back.

"I have a day off tomorrow, and, you know, I will just try to receive some treatment and feel the, you know, the best as possible for my next match," Jankovic said. "I think I will be okay."

Another former No. 1 from Serbia, Ana Ivanovic, moved on without even lifting her racquet on Thursday, as the 16th seed received a walkover into the third round when last week's New Haven runner-up, Petra Cetkovska of the Czech Republic, pulled out of their scheduled encounter.

Ivanovic is a former French Open champ and Aussie Open runner-up.

Meanwhile, 18th-seeded Italian Roberta Vinci vaulted past France's Alize Cornet 6-2, 6-3 and little-known Spaniard Silvia Soler-Espinosa dismissed 31st seed Kaia Kanepi of Estonia 6-4, 6-2 on the grounds at the USTA Billie Jean King National Tennis Center.

In a battle of non-seeds, Spain's Carla Suarez Navarro bested Romanian Simona Halep 3-6, 6-2, 6-2. The 19-year-old Halep stunned French Open champion and Aussie Open runner-up Li Na in her opening match this week.