National champion Saina Nehwal [Images] remains the lone Indian in the Thailand Open after thumping Nguyen Nhung Le Ngoc of Vietnam in straight games to storm into the quarter-finals, even as compatriot Anup Sridhar crashed out of the tournament.

Saina handed out a humiliating 21-9, 21-6 defeat to Nguyen in 22 minutes to earn a meeting with top seed Xingfang Xie of China on Friday.

Sridhar lost 11-21, 26-28 to second seed Boonsak Ponsana of Thailand in 40 minutes.

P Kashyap, the other Indian in the fray, was crushed by local favourite Tanongsak Saensomboonsuk 21-14, 21-19, in 33 minutes.

Meanwhile, seventh seeds Jwala Gutta and Shruti Kurian were shown the door by the Singaporean duo of Shinta Mulia Sari and Lei Yao, who won a fiercely contested first round match, that lasted 43 minutes, 21-17, 15-21, 21-10.