Osaka, Japan (SportsNetwork.com) - Former champion Samantha Stosur was among the winners Monday in the first round of the HP Open, while top-seeded Jelena Jankovic withdrew from the tournament.

Jankovic, coming off a loss to Serena Williams on Sunday in the final of the China Open, cited a left hip injury as the reason for her withdrawal. France's Kristina Mladenovic was elevated to a ninth seed for the event and took Jankovic's place on the top line of the draw.

Stosur, meanwhile, is this week's third seed and cruised past Sweden's Johanna Larsson, 6-4, 6-2, on Monday. The Aussie won this event in 2009 and was the runner-up in 2011.

Last year's champion, Heather Watson of Great Britain, was eliminated Monday by eighth-seeded Monica Puig. The native of Puerto Rico claimed a 6-4, 6-4 victory and will next face Japanese wild card Kurumi Nara, a 6-3, 6-2 winner over France's Caroline Garcia.

Other winners Monday were fifth-seeded Eugenie Bouchard of Canada and Japan's Misaki Doi. Bouchard had little trouble in a 6-3, 6-0 rout of American Varvara Lepchenko, while Doi thumped Spain's Silvia Soler-Espinosa, 6-1, 6-2.

The top player for this event is now second-seeded German Sabine Lisicki. She'll face South Africa's Chanelle Scheepers in the first round on Tuesday.