World champion PV Sindhu made an early exit from the China Open but B Sai Praneeth kept the Indian flag fluttering with a hard-fought straight-game win to reach the men's singles quarter-finals, in Changzhou, China, on Thursday.
Sindhu, an Olympic silver medallist, squandered a first-game advantage to go down 12-21, 21-13, 21-19 to Thailand's Pornpawee Chochuwong in a women's singles pre-quarterfinals that lasted 58 minutes.
Praneeth, who had claimed a bronze medal at Basel, edged out China's Lu Guang Zu 21-19, 21-19 to set up a meeting against Indonesian seventh seed Anthony Sinisuka Ginting.
Ginting beat India's Parupalli Kashyap 23-21, 15-21, 21-12 in a thrilling contest.
Doubles specialist Satwiksairaj Rankireddy also had a dismal day as he suffered twin defeats, losing both the men's doubles and mixed doubles pre-quarter-finals.
In the men's doubles, Satwik and Chirag Shetty, ranked 15th in the world, ran out of steam after a decent start against fourth-seeded Japanese pair of Takeshi Kamura and Keigo Sonoda and went down 19-21, 8-21 in the second-round match that lasted 33 minutes.
This is the second time Satwik and Chirag have lost to the combination of Kamura and Sonoda this year. They had lost to the World No 4 pair at the Japan Open in July.
Satwik then paired up with his mixed doubles partner Ashwini Ponanappa but the duo couldn't get past Yuki Kaneko and Misaki Matsutomo, losing 11-21, 21-16, 12-21 to the Japanese pair.
Ashwini also tasted defeat in women's doubles after she and her partner N Sikki Reddy lost 12-21, 17-21 to second seeded Japanese pair of Misaki Matsutomo and Ayaka Takahashi.
Sindhu, who came into the match with a 3-0 head-to-head lead against Pornpawee, dominated the first game as she lead 7-1 early on but the Thai shuttler reduced the deficit to 10-11 at the break.
However, Sindhu reeled off eight straight points after the interval to jump to 19-10 and eventually sealed the first game comfortably.
In the second game, Pornpawee changed gears and moved to a 5-1 advantage initially. Sindhu clawed back to 7-9 before the Thai youngster jumped to 15-7 with six straight points and held her fort to roar back into the contest.
The decider started on an even note as both the shuttlers fought hard, moving together till 6-6 when Sindhu surged ahead to enjoy a 11-7 cushion at the break.
However, Pornpawee kept breathing down Sindhu's neck and slowly moved to 15-19. From there, the Thai shuttler blasted six straight points to leave the Indian shocked.