PV Sindhu and Kidambi Srikanth notched up contrasting wins to progress to the Round of 16, but World No. 11 H S Prannoy suffered a shock defeat to unheralded Brazilian Ygor Coelho to bow out of the World Championship in Nanjing, China, on Wednesday.
Olympic silver medallist Sindhu, who had got a bye in the first round, opened her campaign with an easy 21-14, 21-9 win over Indonesia's Fitriani.
The 23-year-old Indian, who won the silver medal last year, will face Korean Sung Ji Hyun, a 2015 World Championship bronze medallist, in the next round.
Srikanth, seeded fifth, recovered from a mid match slump during the hard-fought contest to see off Spain's Pablo Abian 21-15, 12-21, 21-14 in a second-round match that lasted 62 minutes.
The Indian, who had clinched four titles last year, will lock horns with Malaysia's Daren Liew, a former world no 10, who had won the 2012 French Open Super Series.
B Sai Praneeth also entered the next round after dumping Spain's Luis Enrique Penalver 21-18, 21-11 to set up a meeting with Denmark's Hans-Kristian Solberg Vittinghus.
However, Prannoy, seeded 11th, couldn't hold on to the momentum after breezing through the opening game to eventually lose 21-8, 16-21, 15-21 to Coelho, ranked 39th in the world.
It turned out to be a disastrous day for the Indian doubles pairs as all of them lost their respective matches to crash out of the prestigious tournament.
Commonwealth Games silver medallists Satwiksairaj Rankireddy and Chirag Shetty did all the hard work but couldn't go the full distance, losing narrowly 18-21, 21-15, 16-21 to world no 8 Denmark pair of Kim Astrup and Anders Skaarup Rasmussen.
Ashwini Ponnapa and N Sikki Reddy were no match for second seeded Japanese combination of Yuki Fukushima and Sayaka Hirota, going down 14-21, 15-21 in the second round.
National champions Manu Attri and B Sumeeth Reddy waged a gallant battle before losing 24-22, 13-21, 16-21 to seventh seed Takuto Inoue and Yuki Kaneko of Japan in men's doubles.
In the singles, Sindhu dished out a dominating game and was always in control of the match. Her superior court coverage and accuracy in strokes made life difficult for the Indonesian.
In the opening game, Sindhu lead 11-7 at the break, before moving to 17-7 with six straight points. She eventually comfortably pocketed the opening game when Fitriani sent the shuttle long.
In the second game, Sindhu continued to surge ahead, moving from 4-5 behind to 8-3 before entering the interval with a 11-5 advantage.
The Indian didn't give Fitriani any chance to make a comeback and quickly wrapped the match when the Indonesia found the net.
Srikanth erased a 2-4 and 6-8 deficit in the opening game before gaining upperhand with a 16-13 lead. He then reeled off four points to reach game points. Pablo tried to recover but the Indian quickly pocketed the opening game.
In the second game, Srikanth had opened up a 6-3 lead but Pablo rode on a six-point burst to move ahead.
The Indian made it 10-12 but the Spaniard registered seven straight points to enjoy a healthy lead to eventually roar back into contest.
In the decider, Pablo managed a slender 11-9 advantage at the break but Srikanth turned the tables and then surged ahead to shut the door on the Spaniard.
"I started off well but made too many mistakes in the second. I was trying too many things and couldn't get going. May be the strategy I tried, I tried too many things and it didn't come off and I have to talk to my coach about it," Srikanth said.
"I should have avoided doing mistakes in the second game and I am concerned about that. The last 10 points, I got everything right. So hope to get things right in the next match," he added.