The 23-year-old Chinese shuttler (left), who beat teammate Wang Xin in three games to win the world crown in 2010, has had a torrid time with injuries since her triumph in Paris two years ago.
The former world No.1 has since fallen to 105 in the world ranking and has been overtaken by a host of Chinese players.
In Bangkok, the unseeded Wang Lin outplayed fourth seeded Indian P. V. Sindhu 21-12, 25-23, in 35 minutes to reach the last eight.
She will now play Chinese qualifier Yu Sun, who edged Thailand’s Busanan Ongbumrungpan 21-12, 21-19. The winner of this match will likely take on second seed and three-time world junior champion Ratchanok Inthanon.
The Thai starlet edged Yao Xue 21-18, 24-22, in the second round and will now face seventh seeded Japanese Minatsu Mitani (below), who beat South Korea’s Park So Young 24-22, 21-14.
In the top half of the draw, top seed Saina Nehwal and third seed Porntip Buranaprasertsuk stayed on course for a semi-final clash after winning their respective matches on Thursday.
Commonwealth Games gold medallist Saina reached the last eight when she trounced Han Li 21-17, 21-13, while Porntip struggled past Lydia Cheah before winning 21-18, 22-20.
In the women’s doubles, unknown Indonesians Imawan Gebby Ristiyani-Nuraidah Tiara Rosalia stunned second seeded Singaporeans Shinta Mulia Sari-Yao Lei 21-16, 16-21, 21-19 52 gruelling minutes.
Also eliminated are former world No. 1s Wong Pei Tty-Chin Eei Hui of Malaysia. The fourth seeds, who will go their separate ways after next week’s Indonesia Open as Pei Tty is retiring, lost 21-15, 21-13 to local favourites Lam Narissapat-Saralee Thoungthongkam.
In the men’s singles, four-time world champion Lin Dan once again dropped another game in the tournament before beating Suppanyu Avihingsanon 21-11, 19-21, 21-10.
The most decorated badminton player in history also had trouble in his opening round match on Wednesday, but still looks a good bet to add this Grand Prix Gold title to his vast collection.
For full results, click here.