Canada's Brian Yang was the most notable casualty from the men's singles event, as action continued at the Badminton World Federation World Junior Championships in Kazan.
The 17-year-old, seeded second, missed out on a place in the last 16 after losing 18-21, 23-25 to China's Ren Cheng Ming at the Kazan Gymnastics Centre in the Russian city.
Ren's reward is a meeting with India's Rohan Gurbani, who defeated Austria's Nicolas Rudolf 21-7, 21-16.
The other seeded players to suffer elimination from the men's singles were eighth-ranked Christian Adinata of Indonesia and 12th-ranked Kok Jing Hong of Malaysia.
Both were beaten by Taiwanese opponents, with Adinata losing 22-20, 16-21, 17-21 to Lin Kuan-Ting and Kok falling to a 21-16, 18-21, 16-21 defeat to Liao Jhuo-Fu.
There were no such problems for top seed Kunlavut Vitidsarn of Thailand, however, as he overcame New Zealand's Edward Lau 21-12, 21-7.
In the women's singles competition, the two seeded players to crash out at the last-32 stage were 10th-ranked Canadian Talia Ng and 13th-ranked Thai Atitaya Povanon.
Ng was beaten 10-21, 21-18, 14-21 by Japan's Akari Kurihara, while Povanon lost 21-14, 14-21, 20-22 to India's Aditi Bhatt.
The top nine seeds are through to last 16 of the women's singles, led by first-ranked Thai Phittayaporn Chaiwan and second-ranked Chinese Zhou Meng.
Chaiwan booked her place by defeating India's Unnati Bisht 21-12, 21-7, while Zhou was too strong for Spain's Ania Setien 21-9, 21-12.