Hosts Hong Kong China rode on their strength in the singles to stun fourth seeds Chinese Taipei in the Badminton Asia Tong Yun Kai Cup.
The home fans had plenty to cheer at the Queen Elizabeth Stadium in Wanchai on Friday night as the host staged a remarkable fight to win both the men's and women's singles to lead 2-1 after losing the men's doubles.
Cheung Ngan Yi turned the tide in the women's singles when Cheung Ngan Yi recovered from a game down to find the rhythm to beat Liang Ting Yu 11-21, 21-6, 21-7 to make it 1-1 on the night.
Chinese Taipei won the opening match of the tie through Lu Ching Yao-Yang Po Han registered a 21-16, 23-21 win over Chang Tak Ching-Yeung Ming Nok in the men's doubles.
Angus Ng Ka Long was next on the court in the men's singles and he too had to come back from a one-game deficit to prevail 17-21, 21-14, 21-17 against Lee Chia-Hao and boost his team's confidence for a 2-1 lead overall.
Gritty Chinese Taipei hauled themselves back into the picture and made it 2-2 when Pai Yu Po-Wu Ti Jung snatched a 21-17, 22-20 win over Ng Wing Yung-Yeung Nga Ting in the women's doubles.
It was left for the mixed doubles to decide the winner and Tang Chun Mann-Ng Tsz Yau responded to beat Hsieh Pei Shan-Tseng Min Hao 22-20, 21-17 to leaving their home fans delighted.
In the semi-finals, on Saturday the hosts will face second seeds and strong title contenders China for a place in Sunday's final.
The Chinese steamrolled Thailand 3-0 in their quarter-final match – winning their mixed doubles, men's singles and men's doubles in straight games.
RESULTS
China beat Thailand 3-0
(China first)
Mixed doubles
He Jiting-Du Yue beat Nipitphon Phuangphuapet-Savitree Amitrapai 21-13, 21-13
Men's singles
Lu Guangzhu beat Kantaphon Wangcharoen 21-13, 21-19
Mixed doubles
Han Chengkai-Zhou Haodong beat Tinn Isriyanet-Tanupat Viriyangkura 21-15, 21-13
Hong Kong China beat Chinese Taipei 3-2
(Hong Kong China first)
Men's doubles
Chang Tak Ching-Yeung Ming Nok lost to Lu Ching Yao-Yang Po Han 16-21, 21-23
Women's singles
Cheung Ngan Yi beat Liang Ting Yu 11-21, 21-6, 21-7
Men's singles
Angus Ng Ka Long beat Lee Chia Hao 17-21, 21-14, 21-17
Mixed doubles
Tang Chun Mann-Ng Tsz Yau beat Hsieh Pei Shan-Tseng Min Hao 22-20, 21-17