JAKARTA — India's P.V. Sindhu caused the first major upset at the World Badminton Championships when the 20-year-old stunned Olympic champion Li Xuerui of China 21-17, 14-21, 21-17 in a pulsating women's singles third round encounter Thursday. Sindhu often saves her best for this tournament and will be looking to improve on her two previous bronze medal performances if she can maintain the form that saw her storm to victory past the third seed in 50 minutes of action in Jakarta. There was also the hint of another upset in same half of the draw when top seed and defending champion Carolina Marin dropped the second game of her match against Taiwan's Pai Yu-po but the injury-prone Spaniard dug deep to advance 21-11, 18-21, 21-17. On a good day for India in the women's singles, second seed Saina Nehwal overcame a sluggish start against Japanese southpaw Sayaka Takahashi to book her place in the last eight with a gutsy 21-18, 21-14 victory over her fast-starting opponent. Meanwhile, archrivals Lee Chong Wei and Lin Dan remained on course for a blockbuster men's singles semifinal showdown with routine third round victories. Chinese fifth seed Lin crushed Denmark's Hans-Kristian Vittinghus 21-9, 21-13 while Malaysia's Lee was given a more thorough test by Wang Zhengming in his 21-17, 21-19 victory. On the other side of the draw, Chinese top seed and defending champion Chen Long put on a supreme display of court coverage with a 21-17, 21-18 victory over unseeded Thai Tanongsak Saensomboonsuk to book his place in the quarterfinals. Fourth seed Kento Momota of Japan also advanced with a 21-15, 21-16 win over Vietnam's Nguyen Tien Minh and second seeded Dane Jan Ø. Jørgensen beat Korea's Son Wan-ho 21-19, 21-11 to set up a last-eight encounter against Lin. The biggest upset of the day came in the women's doubles when top-seeded Japanese pair Misaki Matsutomo and Ayaka Takahashi were stunned in three games (21-15, 12-21, 21-14) by unseeded Malaysian duo Amelia Alicia Anscelly and Soong Fie Cho. Matsutomo and Takahashi were considered one of the few pairs capable of breaking China's stranglehold on the women's doubles event. The Chinese have won every women's doubles crown barring one since they began competing in the world championships 32 years ago. — Agencies