Men's doubles top seeds Marcus Fernaldi Gideon and Kevin Sanjaya Sukamuljo suffered a shock second-round defeat to Choi Sol-gyu and Seo Seung-jae at the Badminton World Federation World Championships in Basel.
The Indonesian pair had looked on course for victory at Saint Jakobshalle when they took the first set against the South Korean pair.
But Choi and Seo fought back to secure a 16-21, 21-14, 23-21 triumph in 64 minutes.
"I think we kept our composure very well at the end,” said Choi.
"We have never played them before but we know they are a great pair and we had to stay focused on every point.
"It’s a great result for us and I hope we can keep going forward at this tournament."
Fifth seeds Hiroyuki Endo and Yuta Watanabe of Japan followed Gibeon and Sukamuljo in crashing out of the tournament after they succumbed 17-21, 22-20, 19-21 to German pair Mark Lamsfuss and Marvin Seidel.
Women's doubles top seeds Maya Matsumoto and Wakana Nagahara breezed to a 21-9, 21-6 victory against Dutch pair Selena Piek and Cheryl Seinen.
In the women's singles draw the top seeds cruised into round three in Basel.
Fourth seed Yu Fei Chen of China won 21-14, 21-19 against Thailand's Pompawee Chochuwong and V Sindhu Pusarla of India defeated Chinese Taipei's Yu Po Pai 21-14, 21-15.
Tzu Ying Tai from Chinese Taipei showed why she is the second seed as she cruised to a 21-15, 21-14 victory against Indonesian Fitriani Fitriani.
Men's fifth seed Anders Antonsen from Denmark safely navigated his passage to round three by defeating Daren Liew of Malaysia 21-17, 21-13.