Women's top seed Michelle Li was knocked out on semi-finals day at the Badminton World Federation US Open in Fullerton.
The Canadian, the Commonwealth Games champion in Glasgow in 2014 and a three-time Pan American Games gold medallist, came unstuck against Kim Ga-eun at the Californian city's Titan Gym.
South Korea's Kim, the third seed, came through 21-16, 21-8 to book her place in the final at the Super 300 World Tour event.
Kim will play China's qualifier Wang Zhiyi who continued her fine run of form to reach a second World Tour final in a row.
The 19-year-old, the silver medallist at the Buenos Aires 2018 Youth Olympic Games, was beaten in the final of the Canada Open last week but came through today against Japan's sixth seed Ayumi Mine.
Wang was a 21-14, 21-11 winner as she chases a first World Tour title.
In the men's singles, Chinese Taipei's qualifier Lin Chun-yi continued his remarkable run to reach the final.
He came from behind to beat compatriot Lin Yu-hsien 15-21, 21-19, 21-17 to book a place in the showpiece game with Thailand's Tanongsak Saensomboonsuk.
Lin's earlier victims at the tournament include Buenos Aires 2018 gold medallist Li Shifeng of China, the Canada Open champion, and South Korea's top seed Lee Dong-keun.
All four men in the semi-finals were unseeded with Saensomboonsuk beating India's Sourabh Verma 21-9, 21-18 to progress.
Both singles finals are tomorrow when the three doubles tournaments will also conclude.
In the men's, second seeds Lee Yang and Wang Chi-lin of Chinese Taipei will take on South Korea's sixth seeds Ko Sung-hyun and Shin Baek-cheol.
Top seeds Nami Matsuyama and Chiharu Shida of Japan will take on fifth seeds Baek Ha-na and Jung Kyung-eun of South Korea in the women's doubles final, while the mixed will pit Chinese Taipei's qualifiers Lee Jhe-huei
and Hsu Ya-ching against France's fourth seeds Thom Gicquel and Delphine Delrue.