Roberta Vinci into QF, American Alison Riske ousted at rainy U.S. Open Roberta Vinci of Italy hits a backhand in her 4th round match against Camila Giorgi of Italy on day eight at the U.S. Open Tennis Championships at the USTA Billie Jean King National Tennis Center in New York City on September 2, 2013. Vinci defeated Giorgi 6-4, 6-2. 2 (UPI) -- Tenth-seeded Roberta Vinci made the quarterfinals for the second straight year but American hopeful Alison Riske took an exit Monday at a rainy U.S. Open. Italy's Vinci made quick work of countrywoman Camila Giorgi 6-4, 6-2 just before heavy rains came down at the USTA Billie Jean King National Tennis Center, necessitating a 4-hour rain delay. Qualifier Giorgi had gained the round of 16 with an upset of former world No. 1 Caroline Wozniacki Saturday. Vinci's next foe will be another Italian, 31-year-old Flavia Pennetta, who racked up five service breaks in her 6-2, 7-6 (7-3) win over 21st-seeded Romanian Simona Halep Monday. The 23-year-old Riske's match against Daniela Hantuchova was held up by rain in the second set, and the delay didn't help her as the Slovakian went on to finish her off 6-3, 5-7, 6-2. Hantuchova reached her first U.S. Open quarterfinal in 11 years with the victory. The weather problems forced the postponement of a scheduled fourth-round match between second-seeded Victoria Azarenka and No. 13 Ana Ivanovic until Tuesday, when the quarterfinals are set to begin.