Defending men's champion Gurusaidutt came through two rounds to reach the last four.
First he outclassed compatriot Mohit Kamat in the pre-quarter finals and then stepped up his play when needed after trailing 4-7 to shut out Chinese Taipei’s Chia Hung Lu 21-12, 21-18.
Thulasi, seeded fourth, could not counter the pace and power of Chinese Taipei’s Chia Tsin Lee, the sixth seed, and went down in straight games.
The Indian shuttler recovered from 0-13 in the second game before losing the quarter-final 14-21, 18-21.
Eighth seeded Sayali, who won the national crown last year at Srinagar, gave a good fight to Chinese Taipei's Yu Chieh Cheng before losing 10-21, 25-23, 21-19 in the pre-quarter-finals.
For the major part of the 60 minute encounter between Sayali and Cheng, the Indian looked most likely to make the last eight stage. But it was Cheng's ability to raise the bar on crucial points that made the difference.
Also knocked out in the pre-quarters was the corresponding men's seed Anup Sridhar, who was beaten 21-15, 21-10 by Taipei's Chia Hung Lu.
Men's fourth seed Saurabh Varma completely dominated his challenger, junior national champion Aditya Joshi, in a one-sided quarter-final to enter the semis with a thumping 21-8, 21-9 victory. He will meet Gurusaidutt on Friday.
Last year's losing finalist and tournament top seed Febby Angguni of Indonesia sailed through to the last four with a 21-8, 21-13 demolition of fifth seeded Indian Saili Rane in their quarter-final.
Results (all Indians unless stated otherwise):
Men's singles (pre-quarter-finals): R M V Gurusaidutt (1) bt Mohit Kamat 21-15, 21-19; Chia Hung Lu (TPE) bt Anup Sridhar (8) 21-15, 21-10; Sourabh Varma (4) bt Yi-Hsiang Yang (TPE) 21-7, 21-15; Aditya Joshi bt Neeraj Vashist 16-21, 21-10, 21-14; Chetan Anand (6) bt Mohamed Ajfan Rasheed (MDV) 21-15, 21-9; H S Prannoy (3) bt Talar Laa 21-15, 21-13; Sheng-Jie Yang (TPE), def. Harsheel Dani 14-21 21-19 21-19; B Sai Praneeth (2) bt Aditya Prakash 21-14, 21-12.
Quarter-finals: R M V Gurusaidutt (1) bt Chia Hung Lu (TPE) 21-12, 21-18; Saurabh Varma (4) bt Aditya Joshi 21-8, 21-9.
Women's singles (Pre-quarter-finals): Febby Angguni (1) (INA) bt Arathi Sara Sunil 21-14, 21-4; Saili Rane (5) bt Wen Chi Hsu (TPE) 19-21, 21-19, 21-14; Dinar Dyah Ayustine (INA) bt Neha Pandit 21-14, 21-7; Yu Chieh Cheng (TPE) bt Sayali Gokhale (8) 10-21, 25-23, 21-19; Chia Hsin Lee (6) (TPE) bt Lekha Handunkuttihettige (SRI) 18-21, 21-14, 21-9; P C Thulasi (4) bt Mohita Sahdev 21-17, 21-14; Trupti Murgunde (7) bt Riya Pillai 21-13, 21-15; Ana Rovita (INA) bt Karishma Wadkar 21-12, 21-11.
Quarter-finals: Chia Hsin Lee (6) (TPE) bt P C Thulasi (4) 21-14, 21-18; Febby Angguni (1) (INA) Saili Rane (5) 21-8, 21-13.
Mixed doubles (Quarter-finals): Kona Tarun and Ashwini Ponnappa (1) bt Tien Tzu Chieh-Ching Hui Chang (TPE) 21-14, 21-17; Pranaav Jerry Chopra-K Maneesha (4) bt Chee Tean Tan-Shevon Jemie Lai (MAS) 21-15, 21-16; Akshay Dewalkar-Pradnya Gadre (3) bt K Nandagopal-N Siki Reddy 21-10, 21-17; Arun Vishnu-Aparna Balan (2) bt Ko-Chi Chang-Hsin Tien Chang (TPE) 21-18, 21-13.
Image: R M V Gurusaidutt