London Olympics bronze medallist Saina, who is coming back from an ankle injury, gave ample display of her powerful game as she overcame Sindhu 21-13 21-19 in an all-Indian women's singles quarterfinal clash.
"I m happy to b on the winning side against Sindhu today ... It was a really tough match," Saina tweeted after the match that lasted 37 minutes.
Saina, who has a silver and a bronze at World Championships, will next face Thailand's Ratchanok Intanon, seeded fourth, who dumped Glasgow World Champion Nozomi Okuhara of Japan in another match.
Young men's doubles pair of Satwiksairaj Rankireddy and Chirag Shetty stunned fourth seeded and World No 6 Denmark pair of Mads Conrad-Petersen and Mads Pieler Kolding 21-23 21 -15 19-21 in a match that lasted an hour and six minutes.
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The World No 32 Indian pair, who had beaten the Danish pair at the French Open pre-quarterfinals last year, fought back from 9-11 and 12-16 in the decider to eke out the hard- fought win.
Satwik and Chirag, who had reached the quarters at Korea Open as well last year, will face top seeds Indonesian pair of Marcus Fernaldi Gideon and Kevin Sanjaya Sukamuljo next.
Playing Sindhu for the first time outside India, Saina produced her best and never let the advantage slip after leading 3-0 early on in the first game.
Despite Sindhu fighting back and making it 4-4, Saina continued to dominate the proceedings and entered the break with 11-9 advantage.
The 27-year-old continued her good run after the interval, increasing her lead to 18-10 at one stage. Sindhu manage to win three more points before the senior shuttler grabbed the opening game.
Sindhu then managed to enter the lemon break with a slender 11-10 advantage. The duo fought tooth and nail till 14-14 before engaging in a long rally which left both gasping for breath.
But at the end of it, Saina had managed to lead 15-14, which she increased to 17-14.
The World No 3 and second seed, Sindhu tried to claw back but Saina managed to keep her nose ahead and shut the door on her younger compatriot to reach her first semifinal since the World Championship in August last year.
London Games bronze medallist, Saina had, however, upstaged Sindhu to clinch the women's singles title in the Senior National Badminton Championship last year.