Fifth-seeded Eugenie Bouchard of Canada ousted Varvara Lepchenko of the United States 6-3, 6-0 on Monday to advance to the second round of the Japan Women’s Open.
Also moving on is No. 3 Samantha Stosur of Australia, who defeated Johanna Larsson of Sweden 6-4, 6-2 in Osaka.
The 29-year-old Stosur didn't face a break point on her serve and converted three of nine break points in the match at Ustubo Tennis Park.
Stosur has had previous success in the Osaka tournament. She won here in 2009, was runner-up in 2011 and a semifinalist in 2012, compiling a 15-3 record in Osaka.
In other first-round matches, seventh-seeded Monica Puig of Puerto Rico beat defending champion Heather Watson of Britain 6-4, 6-4.
Top-seeded Jelena Jankovic pulled out, citing a left-hip injury. The Serbian player received medical treatment in the second set of her 6-2, 6-2 loss to Serena Williams in Sunday's final of the China Open in Beijing.