Praneeth, who had reached the semifinals of the Japan Open last week, maintained his good run to enter the last-eight stage after registering a 21-18, 21-19 victory over compatriot Shubhankar Dey. He will now face Kanta Tsuneyama of Japan in the quarterfinal.
There was also some good news for India in the men's doubles section as the pair of Satwiksairaj Rankireddy and Chirag Shetty sailed into the quarterfinals after registering a 21-17, 21-19 win over the Indonesian duo of Fajar Alfian and Muhammad Rian Ardianto. The Indian pair will now take on Korea's Choi Solgyu and Seo Seung Jae in the next round on Friday.
In mixed doubles, the Indian pair of Satwiksairaj Rankireddy and Ashwini Ponappa defeated Alfian Eko Prasetya and Marsheilla Gischa Islami of Indonesia 21-18, 21-19 to enter the next round. However, the other Indian pair of Pranaav Jerry Chopra and N. Sikki Reddy went down against Tang Chun Man and Tse Ying Suet of Hong Kong 16-21, 11-21.
Earlier in the day, seventh seed Saina, who won against Thailand's Phittayaporn Chaiwan in the opening round, squandered a lead to lose 21-16, 11-21, 14-21 against unseeded Sayaka Takahashi of Japan in a match that lasted 48 minutes.
In the absence of Olympic medallist P.V. Sindhu, who withdrew from the event in the last minute, Saina's ouster marks the end of India's campaign in women's singles.
The world number eight was competing at the Thailand Open after a two-month injury lay-off, which forced her to miss the Indonesia Open and Japan Open.
In men's singles, Srikanth lost 21-11, 16-21, 12-21 to Thailand's Khosit Phetpradab in a second round duel which lasted less than an hour. Parupalli Kashyap also lost his second round contest to Chou Tien Chen of Taiwan 9-21, 14-21 in 33 minutes.
( With inputs from IANS )