Kim booked his place in the quarter-finals of the tournament with a shock 21-12, 21-12 win over his fellow South Korean at the Yeomju Gymnasium.

He will take on Chia Hao Lee in the last eight after the player from Chinese Taipei overcame Joo Ven Soong of Malaysia 21-19, 21-13.

Indonesia's Panji Ahmad Maulana, who accounted for Thailand's third seed Tanongsak Saensomboonsuk yesterday, continued his progress at the BWF Grand Prix Gold event by beating Lin Chia Hsuan of Chinese Taipei.

Maulana recorded a battling 20-22, 21-18, 21-19 win to set up a quarter-final meeting with 11th seed Lee Dong-keun.

Lee reached the next round of the event thanks to a gruelling 21-17, 21-23, 21017 success.

Fourth seed Jeon Hyeok-jin of South Korea joined his compatriot by ousting Ihsan Maulana Mustofa 21-12, 21-15.

Women's singles top seed Sung Ji-hyun avoided the same fate as Son but had to survive a scare during her last 16 encounter with Zhang Yiman of China.

Sung was made to work hard for her place in the quarter-finals as she sealed a 14-21, 21-13, 25-23 victory in a match which lasted an hour and 10 minutes.

Zhiyi Wang, a 21-13, 21-12 victor over Sonila Cheah of Malaysia, awaits for Sung in the last eight.

Nitchaon Jindapol of Thailand, the second seed, is also through as she swept aside Min Ji-lee of South Korea 21-12, 21-15.

Jindapol will face Lee Chia Hsin of Chinese Taipei in the last eight.

The tournament in the South Korean city is due to continue tomorrow.