The men's singles competition at the Badminton World Federation's Korea Open opened up dramatically today as defending champion Anthony Ginting was beaten in his quarter final by Chinese Taipei's Chou Tien Chen.
It came with second seed Kento Momota, Japan's Asian and world champion, unable to contest his quarter-final because of injury at Seoul's SK Handball Stadium.
Ginting, whose season hit the heights last week as he beat the all-conquering Momota in the China Open final, was beaten in just 39 minutes by Chou, who earned a 21-13, 21-11 scoreline.
Chou's semi-final opponent will be Japan's Kenta Nishimoto, who received a walkover from his injured compatriot Momota.
Meanwhile, the player Ginting beat in last year's final, his Indonesian compatriot Jonatan Christie, progressed.
The Asian Games champion beat China's Zhao Junpeng 21-17, 21-16.
"This is the first semi-final for me in 2018, so I'm very very happy," the Indonesian said.
"After the Asian Games, I was a bit tired, and there was no time to prepare for the next three tournaments.
"In Japan and in China I lost early.
"So today I'm happy that in the last tournament of the Asian leg I reached the semi-finals."
Christie now faces senior compatriot Tommy Sugiarto, who outplayed Korean qualifier Heo Kwang Hee in three games, winning 15-21, 21-19, 21-9.
Nozomi Okuhara reached her third consecutive World Tour semi-final in the women's event after surviving four match points.
Japan's 2017 world champion eventually defeated an exhausted Saina Nehwal of India 15-21, 21-15, 22-20.
Okuhara takes on compatriot Akane Yamaguchi, while in the other semi-final, home hope Sung Ji Hyun faces Beiwen Zhang of the United States, who beat Scotland's unseeded Kirsty Gilmour 21-15, 21-19.