London Olympics bronze medallist Saina staved off a spirited challenge from World No 44 Mette Poulsen of Denmark 21-19, 23-21 in a 46-minute match.
Sindhu had resumed training last month under the supervision of Korean coach Park Tae-Sang after the Sports Authority of India
The badminton player walked for footwear designer Misfit Panda.
The shuttlers led by Saina Nehwal will make their first appearance in the Olympic Games on Thursday along with men golfers as India still waits for its first medal after five days of fruitless labour in this Brazilian city.
The world body has so far maintained that it has no plans to make any adjustments to the regulations related to the Tokyo Games qualification period and that other events will go as per schedule.
Two-time champion Saina Nehwal and HS Prannoy progressed to the quarter-finals after straight-game victories in the women's and men's singles respectively at the $ 120,000 Swiss Open Grand Prix Gold badminton tournament, in Basel.
World No 1 shuttler Saina Nehwal presented the racquet with which she won a silver medal at the Badminton World Championships to Prime Minister Narendra Modi as an advanced birthday present, on Wednesday.
Prime Minister Narendra Modi congratulated shuttlers Saina Nehwal and K Srikanth for their victories at the China Open Super Series tournament on Sunday.
Former world No. 1 Kidambi Srikanth's wretched run continued as he went down 6-21, 17-21 to fellow-Indian Ajay Jayaram, diminishing his hopes of qualifying for the Tokyo Games.
Returning to action after nearly two months, Saina, who made last-minute withdrawals from Indonesia Open and last week's Japan Open because of injuries, got past Chaiwan 21-17, 21-19 in her opening round contest.
The lack of competitions before the Olympics is a major concern for Indian shuttlers but not so much for PV Sindhu, who trusts her Korean coach Park Tae Sang to create match situations for her in training itself.
A summary of sports events and persons who made news on Saturday
Many celebrities including cricket icon Sachin Tendulkar and legendary singer Lata Mangeshkar rallied around the central government on social media using hashtags #IndiaTogether and #IndiaAgainstPropaganda following tweets by Rihanna and climate activist Greta Thunberg backing farmers who are protesting near Delhi border.
Jwala says Sindhu should scan through all the videos of her past matches and work on her strategy.
Chirag said "it is difficult to stay motivated" in such uncertain times.
After a shocking exit from the Rio Olympics, Saina Nehwal cited an inflammation in her right knee as the reason for her hampered on-court movement.
As Parineeti Chopra brings Saina Nehwal's story on screen, Joginder Tuteja takes a look at how well Bollywood's sports movies have done at the box office.
Taking a jibe at pugilist Vijender Singh and badminton ace Saina Nehwal after the duo advertised their names for the Padma Bhushan, former Jammu and Kashmir chief minister Omar Abdullah said it's a great pity that the Indian athletes feel they have to lobby and threaten to receive awards.
India's ace shullter Saina Nehwal put up a strong fight but went down 13-21, 21-13, 6-21 to World No 1 Tai Tzu Ying in Denmark Open final on Sunday.
Indian batting mainstay Virat Kohli, tennis star Sania Mirza and top-seeded badminton player Saina Nehwal lead the pack of over 50 Indians in Forbes' inaugural list of top promising young leaders and game changers under the age of 30 in Asia.
The quarter-finals bug bit Saina Nehwal yet again at the badminton World Championships.
India's shuttlers suffered a mild hiccup before making it to the Mixed Team badminton final at the Commonwealth Games on Sunday. After an easy passage to the semi-finals, they were checked in their stride by Singapore before winning the first semi-final 3-1.
The Italians are playing tennis from their balconies. What are you doing?
Sindhu said she has to watch out for the Chinese players as well since they have been missing from the circuit for some time.
Saina Nehwal, who won the tournament last year before going through a lean patch, lost 19-21, 13-21, 5-21 to Sayaka Takahashi in 50 minutes.
But Saina, who had lost in the quarter-finals last year, is set to gain 3600 points having made it to the World Championships final this year. Saina will therefore, now have 82, 792 points to her tally, giving her the World No 1 title again.
The first Indian woman to clinch a silver medal at the World Championship in the 2015 edition at Jakarta, Saina has been struggling ever since, limping out of the Olympics last year with a knee injury.
Saina Nehwal's personal coach Vimal Kumar is happy that the newly crowned Australian Open Super Series champion "attacked well" and displayed more determination during her hard-earned win over China's Sun Yu.
Ace tennis player Sania Mirza said India still needs to do a lot more to bring women at par with men in sports, though the country has come a long way in this aspect.
All eyes will be on Indian ace Saina Nehwal when she returns to the court after an injury lay-off at the All England Championship, hoping to better last year's runner-up finish at the prestigious event which begins with the qualifiers in Birmingham.
Sameer Verma stayed on course for his title defence while three-time former champion Saina Nehwal too reached the semifinals with an easy win
Saina, who was looking good at the start of the season, was diagnosed with acute gastroenteritis with mild pancreatitis which affected her performance at the All England Championship.
Summary of sports events and persons who made news on Monday
In an interview with PTI, the Hyderabadi also reveals why she parted ways with the former All England champion and throws light on the Padma controversy.
Rio Olympic silver medallist Sindhu, who made early exits at the China Open and Korea Open, dropped to the 6th spot after five months and the former World No 2 shuttler will look to make amends at the Denmark Open and French Open.
Saina Nehwal once again faltered at the semi-final stage as she suffered a straight game defeat at the hands of China's Wang Yihan in the women's singles at the Asia Badminton Championships, in Wuhan, China, on Saturday.
'NO one is more selfless and brave than a soldier.'
Indian shuttler B Sai Praneeth sailed into the semi-finals of the of the $ 120000 Thailand Grand Prix Gold after registering a straight-game win over local player Kantaphon Wangcharoen in Bangkok on Friday.
Saina Nehwal remained static at second position while Kidambi Srikanth dropped a place to be at ninth spot in the world badminton rankings released on Thursday.
Ace Indian shuttler Saina Nehwal moved one place up to occupy the fifth spot while P V Sindhu remained unchanged at 10th in the latest Badminton World Federation Rankings issued on Thursday. Saina, who clinched her second Australian Open title earlier this month, exchanged places with Japan's Nozomi Okuhara, who now occupies the sixth spot in the women's singles list headed by Spain's Carolina Marin.