Thailand's Phittayaporn Chaiwan defeated Taiwan's Pai Yu-po 21-18, 21-13 in the opening round of the BWF World Championships in Tokyo on Tuesday.
Phittayaporn, 21, will face compatriot and eighth seed Ratchanok Intanon in the women's singles second round (last 32) on Wednesday.
Ratchanok, 27, is seeking her second world title following her success in 2013.
In the men's singles, Thailand's Sitthikom Thammasin beat Malaysia's Ng Tze Yong 21-9, 10-21, 21-19 to reach the third round.
He will next meet Denmark's world No.1 Viktor Axelsen, who finished off Mark Caljouw of the Netherlands 21-19, 21-10.
China's Shi Yuqi, who is returning from a 10-month ban imposed by the Chinese Badminton Association, continued his comeback with a 21-13, 21-16 second-round win over Denmark's Rasmus Gemke.
Elsewhere, reigning women's champion and top seed Akane Yamaguchi cruised through her opening match.
Japan's Yamaguchi beat Indonesia's Gregoria Mariska Tunjung 21-12, 21-15 in the second round in front of an appreciative home crowd to kick off her hunt for a second straight world title.
"I wasn't really nervous but you do get players who lose in the first round and go straight out, so I was really focused on getting the result," said 25-year-old Yamaguchi.
"I never felt that I had any breathing space until towards the end of the second game. It was more about dealing with my opponent than me going on the attack."
Spain's Carolina Marin, who is aiming to win a record fourth world title, got her campaign off to a steady start with a 21-16, 21-14 win over Canada's Wen Yu Zhang in the second round.
Former world No.1 Marin endured a horror 2021, missing both the pandemic-delayed Tokyo Olympics and the world championships in her hometown of Huelva after suffering an ACL injury.
Marin returned to action in April this year but she said yesterday that she was "not 100 percent yet".
"This is the condition that I have right now and I have to play in this condition," said Marin, seeded number five for the competition.
"Let's see how far I can go in this tournament. Of course I want to get a medal here and I want to win, but this is not something I have in my mind."
There were also second-round wins for South Korean third seed An Se-Young, who beat Vietnam's Thuy Linh Nguyen 21-18, 21-10, and India's Saina Nehwal, who beat Hong Kong's Cheung Ngan Yi 21-19, 21-9.
