Satwik-Chirag edged past Danish fourth seeds Mads Conrad-Petersen and Mads Pieler Kolding 23-21, 15-21, 21-19 in an hour and six minutes.
Saina, the 2012 Olympic bronze medallist, moved past 2016 Olympic runner-up and second seed Sindhu 21-13, 21-19 in 37 minutes in a quarter-final.
The singles match was between the two most popular faces of Indian badminton. The contest between the Pullela Gopichand Academy products was expected to be a top match but 23-year-old Sindhu flattered to deceive. Saina, 22, was too hot to handle for Sindhu.
Saina was quick to get off the blocks, holding a 3-0 lead before making it 9-5. Sindhu did some hard work to go into the mid-game break trailing by two points.
After the break, Saina upped the ante and kept dictating the pace of the game to reel off consecutive birdies to sit on a 15-9 lead. Afterwards, it was easy for Saina to pocket the first game.
In the second game, Sindhu came out strongly. The three-time World Championship medallist rode ona five consecutive points to have a 10-5 lead. But Saina didn't take long fight her way back, equalising at the 10-point mark before trailing by a point at the mid-game break.
Saina brought all her experience into play as she wriggled out of a difficult situation to lead 15-14. From here, there was no looking back for her, winning the second game 21-19.
"I m happy to b on the winning side against Sindhu today," Saina wrote on Twitter.
With this win, 27-year-old Saina has taken a 2-1 lead in head-to-head records against her Hyderabadi rival.
In the semi-finals on Saturday, Saina will face Thai fourth seed Ratchanok Intanon, who defeated reigning world champion and Japanese sixth seed Nozomi Okuhara 21-17, 21-10.
The other semi-final will see China's He Bingjiao face Taiwanese world No. 1 Tai Tzu-ying.
Bingjiao upset Spanish two-time world champion and reigning Olympic champion Carolina Marin 21-19, 12-21, 21-16, while Tai defeated South Korean Sung Ji-hyun 21-11, 21-8 in just 29 minutes.
In the doubles match, unseeded Satwik-Chirag didn't care about the reputation of Petersen-Kolding. They played aggressive badminton to take the first game 23-21. A strong start enabled them to lead for the better part of the first game. The Danish pair worked hard to make the match out of it after the 15-point mark.
But the experienced Danish pair took the match to the third game by winning the second game 21-15. A 12-2 lead for Petersen-Kolding meant that the writing was on the wall.
The third game saw no pair got headway till the 12-point mark. Afterwards, Petersen-Kolding broke away, holding a 16-12 advantage.
But the Indians showed a lot of courage in clawing their way back by snatching four points on the trot. Another see-saw battle followed before Satwik-Chirag clinched it 21-19.
In the semi-finals, the Indian pair will meet the Indonesian top seeds Marcus Fernaldi Gideon and Kevin Sanjaya Sukamuljo.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
