Sania Mirza during her match against Japanese Ayumi Morita in Tokyo on Monday. (AFP)

New Delhi: Sania Mirza started her Japan Open campaign in style by out-playing local hope Ayumi Morita 6-0, 6-4 in the first round of the $1,75,000 WTA tournament in Tokyo on Monday.

The Indian, seeded second, is playing her first match since the US Open. She pulled out of the Sunfeast Open in Calcutta due to a wrist injury.

Sania next faces Australian Cassey Dellacqua in the second round of this Tier III event. Dellacqua beat Severine Bremond of France 6-4, 6-0.

Sania, partnering American Christina Fusano, will begin her doubles campaign on Tuesday against Urszula Radwanska of Poland and Agnes Szatmari of Romania.

The tournament saw its first upset when seventh seed Aiko Nakamura of Japan lost 3-6, 4-6 to Czech Republic’s Klara Zakopalova.

Former world No. Venus Williams, winner of the Korea Open title at the weekend, heads the women’s field.

The men’s event, already reeling from the withdrawal of world No. 1 Roger Federer, began with players scuttling on and off court because of rain.

Federer blamed fatigue for his decision to not defend his title in the Japanese capital.

His absence leaves world No. 8 David Ferrer as the tournament’s highest-ranked player and top seed.

Fans who braved Monday’s cold weather were treated to Taiwanese Lu Yen-hsun’s 6-7, 7-6, 6-1 victory over Thai Danai Udomchoke.

Japan’s 17-year-old Kei Nishikori lost his first professional match against American Zack Fleishman 6-7, 6-3, 1-6. German Mischa Zverev beat Italy’s Fabio Fognini 6-1, 7-6 to advance, while Spain’s Ivan Navarro overcame Dutchman Robin Haase 7-6, 7-6.