Alisa Kleybanova defeated Schiavone, seeded fifth, 6-7 (5-7), 6-1, 6-2 by piling up five service breaks while facing only one break point in the second and third sets.
Jankovic is just 2-7 in five tournaments since last year's U.S. Open after falling to Aravane Rezai 7-5, 2-6, 6-3. Rezai dropped serve seven times -- four in the second set -- but also broke Jankovic's serve seven times.
No. 4-seeded Samantha Stosur collected a 7-5, 6-4 victory over Yanina Wickmayer, getting a break in each set and not facing a break-point situation.
Also, seventh-seeded Victoria Azarenka fought off Ekaterina Makarova 2-6, 6-2, 6-4 and No. 8-seeded Li Na was a 6-1, 6-2 winner over Anastasia Rodionova.
Other first-round winners included Dominika Cibulkova, Maria Jose Martinez Sanchez, Barbora Zahlavova Strycova and Shahar Peer. Also advancing to the second round were Virginie Razzano, Bojana Jovanovski and Flavia Pennetta.