The 21-year-old from Hyderabad has 69399 points in her kitty, while London Olympics bronze medallist Saina Nehwal is the only other Indian woman in the top 10 at ninth position.
The Rio silver medallist was previously ranked sixth, behind Ratchanok Intanon of Thailand, whom she dethroned to acquire the fifth spot.
Saina and Sindhu decided to skip the tournament to prepare for the upcoming hectic international schedule which includes All England Championship.
Saina had earlier also tweeted a hilarious video featuring her sister.
Lee had said last month that he hoped to win the 2017 BWF World Championships in Scotland in August before retiring.
The 34-year-old, will be out for weeks after he slipped and fell at the new Academy Badminton Malaysia.
Sindhu, and Saina,will be sharing the responsibility in the women's singles.Sameer Verma, will in men's singles.
Former champion Varma, seeded third, defeated Nikhilesh Sarma 21-10 21-12.
In some of the most exciting matches of the opening day, Siddharth Pratap Singh staved off a spirited challenge from Adrian George 25-27 21-17 21-16.
Sen hails from Almora district in Uttarakhand.
In the women`s singles clash, Sindhu ended unseeded Indonesian Grigoria Mariska`s dream run.
Sameer will be up against Indian ninth seed Sai Praneeth, who edged past third seed Kidambi Srikanth 15-21, 21-10, 21-17 in 59 minutes.
Sindhu tested the conditions at the Babu Banarasi Das Indoor Stadium en route to her easy 21-9 21-11 win over compatriot Prabhudesai.
Seeded top, Sindhu will face Anura Prabhudesai in the opening round and is likely to clash with fourth seed Fitriani Fitriani in the semifinals if she doesn't suffer any hiccups.
The 26-year-old former World Number One had endured an injury-plagued 2016 season.
The top-seed registered a solid 22-20, 22-20 triumph over 19-year-old Chochuwong in a thrilling summit showdown.