Saina reached the final eight with an easy 21-15 21-9 win over Rituparna Das, top seed Srikanth beat Malaysia's Iskandar Zulkarnain Zainuddin 22-20 20-22 21-11 in a men's singles match.
Olympic bronze medallist Saina will next face Arundhati Pantawane, who defeated Spain's Beatriz Corrales 22-20 22-20, while Srikanth meets fifth seed Wei Feng Chong of Malaysia.
Sindhu lived up to her reputation as the third seeded Indian got past Singapore's Jiayuan Chen 21-18 21-14 and next faces Thailand's Porntip Buranaprasertsuk.
Eighth seed PC Thulasi beat Russia's Evgenia Dimova 21-7 21-15, she next faces fourth seed Nichaon Jindapon of Thailand.
World champion Carolina Marin beat Tanvi Lad 23-21 19-21 6-21.
In the men's singles Parupalli Kashyap, seeded third, beat 11th seed Misha Zilberman of Israel who conceded the match.
Kashyap will next take on Singapore's Zi Liang Derek Wong.
Sixth seed B Sai Praneeth edged out Thailand's Suppanyu Avihingsanon 21-16 24-26 21-13 in another men's singles clash.
RMV Gurusaidutt saw off Thailand's Thammasin Sitthikom 21-16 21-19. Fourth seed H S Prannoy made it through when Russia's Vladimir Ivanov retired injured.
Arvind Bhat lost to Malaysia's Wei Feng Chong 6-21 11-21, while seventh seed Sourabh Varma lost 21-16 17-21 16-21 to Derek Wong.