NEW HAVEN - Camila Giorgi sprang an upset to defeat four-time champion Caroline Wozniacki 6-4, 6-2 on Wednesday and reach the quarter-finals of the WTA Connecticut Open, a final warm-up for the US Open.The Italian saw off the former world number one in 78 minutes to book a last-eight date with Spain’s Garbine Muguruza, who eliminated Chinese qualifier Peng Shuai 6-2, 3-6, 6-3 in another second-round match. The unseeded Giorgi also ousted Wozniacki in last year’s US Open, but lost their only other meeting this year at Eastbourne. Wozniacki, whose best Grand Slam showing was a 2009 US Open runner-up effort, won the title at New Haven from 2008 to 2011, but saw her record at the Yale University event dip to 24-3.The 24-year-old Dane’s only prior losses since Wimbledon came in three-set battles with world number one Serena Williams in Montreal and Cincinnati.Wimbledon finalist Eugenie Bouchard also failed to make it to the quarter-finals. Australian veteran Samantha Stosur briskly ousted the third-seeded Canadian 6-2, 6-2. Stosur next faces Belgian Kirsten Flipkens, who beat Germany’s Andrea Petkovic 4-6, 7-6 (7/4), 7-6 (8/6). Thursday’s other two quarter-finals were already set. Slovakian Magdalena Rybarikova, who ousted top-seeded Simona Halep, will take on American Alison Riske, and second-seeded Wimbledon champion Petra Kvitova will face fellow Czech Barbora Zahlavova Strycova.