Choe and Yoo defeated Alvaro Robles and Galia Dvorak of Spain 3-2 (8-11, 11-9, 8-11, 11-9, 13-11) in a qualification match Tuesday. But they will face an uphill battle against Lee-Jeon, considered the top South Korean pair that has a chance to contend for gold at the Asian Games in August.

The Choe-Yoo team is one of four joint Korean pairs competing at the Korea Open.

Also in the round of 16, another unified mixed doubles team, Jang Woo-jin (South Korea) and Cha Hyo-sim (North Korea), will take on the second-seeded team from Hong Kong, Wong Chun Ting and Doo Hoi Kem.

Jang and Cha booked a spot in the round of 16 after their Mongolian opponents, Battumur Baatar and Delgermaa Mergen, withdrew from their qualification match Tuesday.

The Koreas have a unified team each in the men's and women's doubles, whose round of 16 action will also begin Thursday.

On the men's side, the fifth seed Lee Sang-su (South) and Pak Sin-hyok (North) have teamed up. Suh Hyo-won (South) and Kim Song-i (North) will play together in the women's event.

The tournament runs through Sunday. (Yonhap)