OSAKA, Japan -- Top-seeded Jelena Jankovic pulled out of the Japan Women's Open because of an injured left hip.
The Serbian received medical treatment in the second set of her 6-2, 6-2 loss to Serena Williams in Sunday's China Open final in Beijing.
In Monday's first round, third-seeded Samantha Stosur of Australia defeated Johanna Larsson of Sweden 6-4, 6-2. Stosur won in Osaka in 2009, was runner-up in 2011 and a semifinalist in 2012.
Also at Ustubo Tennis Park, seventh-seeded Monica Puig of Puerto Rico beat defending champion Heather Watson of Britain 6-4, 6-4, and fifth-seeded Eugenie Bouchard of Canada ousted Varvara Lepchenko of the U.S. 6-3, 6-0.