Indian star shuttler Saina Nehwal entered the pre-quarterfinal of Japan Open Badminton Tournament.Saina defeated Enthanon Rachnock of Thailand 21-17, 21-10 in first round of women's singles in Tokyo today. Saina will next face Singapore's Ming Tyan Fu. The Indian pair of Jwala Gutta and V.Diju also entered the pre-quarterfinal of mixed doubles. They beat Japan's Shintaro Ikeda and Reiko Shiota 22-20, 21-15. The duo will now take on Taiwan's Hung Ling Chen and Ven Sing Chen.