Nanjing (China), Aug 3: Women's singles star P.V, Sindhu was the lone Indian to enter the semi-finals of the Badminton World Championships, with Saina Nehwal, B. Sai Praneeth and the mixed doubles pair of Satwiksairaj Rankireddy and Ashwini Ponnappa losing in the quarter-finals here on Friday.Third seed Sindu, facing Japanese Nozomi Okuhara, who defeated her at the previous edition's final, won 21-17, 21-19 in 58 minutes. In both games, Okuhara was strong at the beginning but once Sindhu caught up with her, the Japanese failed to control the Hyderabadi, who came into the match with a 6-5 record in head-to-head.In the semi-final, three-time World Championships medallist Sindhu will take on another Japanese, second seed Akane Yamaguchi, who ousted Chinese fifth seed Chen Yufei with a 21-13, 17-21, 21-16 victory in an hour and eight minutes.Earlier in the day, Saina, the 10th seed, was outclassed by Spanish seventh seed and two-time world champion Carolina Marin, who cruised to a 21-6, 21-11 victory in 31 minutes to move into the last four round.The win was Spaniard Carolina's fifth in 10 meetings against the veteran Indian, a two-time medallist at the World Championships.On Saturday, Carolina will meet China's sixth seed He Bingjiao, who eliminated top seed Tai Tzu Ying of Chinese Taipei with a 21-18, 7-21, 21-13 win.With five titles from six events this year, Tai headed into the World Championships as the overwhelming favourite. However He, world no. 7, had a better start by narrowly taking the first game 21-18, reports Xinhua news agency.In the second game, Tai appeared to have things under control with an 8-0 lead and eventually leveled the match by winning the set 21-7.But Tai fell apart again in the decisive set as He maintained the lead from the early start and cruised to victory, the biggest upset at this year's tournament so far."Today I made several mistakes in the third set, and also had some simple faults in the opening set," admitted Tai. It's only the second loss for Tai this year in 36 matches.India also had disappointments in the mixed doubles, with the unseeded pair of Satwik and Ashwini falling to Chinese top seeds Zheng Siwei and Huang Yaqiong 17-21, 10-21 in 36 minutes.In the men's singles, B. Sai Praneeth lost 12-21, 12-21 in 39 minutes to Japanese sixth seed Kento Momota. The Indian couldn't match up to the speed, accuracy and power of the rising star from Japan.Top seed Viktor Axelsen was edged out by China's two-time world champion Chen Long as the Dane became the fourth reigning world No.1 to bid farewell to the tournament. Chen prevailed 21-19, 21-11 in 59 minutes.Axelsen was the attacking side in the majority of the match, jumping up high to unleash ultra-fast smashes from time to time. But Chen's patience paid off as the Dane committed frequent faults, which made him swing his racket with anxiety. Chen seized the game point at 20-18 when Axelsen's return was called out and the video review said the same. The eighth seed successfully converted the game point and earned himself a 1-0 advantage.Chen sustained his momentum into the second game while the defending champion was still troubled by errors. A last "out!" by the line judge confirmed Axelsen's elimination after a 11-21 loss.Chen Long will take on compatriot Shi Yuqi in the semi-finals on Saturday after the latter got past Chinese Taipei's seventh seed Chou Tien Chen 16-21, 21-15, 21-18.Chen, the Olympic gold medallist holds a 4-1 head-to-head advantage against his teammate but was bested in their last encounter in the quarter-finals of the All-England Open this year.