Lee Cheuk-yiu stunned former badminton world number one Viktor Axelsen to stroll into the semi-finals of his home Hong Kong Open on Friday.
The tournament has ploughed on despite pro-democracy protests in the city and Lee will play India's Kidambi Srikanth in the last four on Saturday.
Unseeded Lee defeated the Dane Axelsen, the seventh seed, 21-14, 21-19 in their quarter-final.
"My opponent played very well today and I didn't control the shuttle under the conditions, so of course very disappointed about that," said Axelsen.
"I had problems reading his shots."
Lee, the world number 27 from Hong Kong who on Thursday defeated China's third seed Shi Yuqi, said: "The fans made a big difference.
"The pressure was on him, I only thought of pressing forward all the time.
"He's so much taller than me so I had to be aggressive. I wouldn't have a chance if he got a big lead."
The Hong Kong Open is one of the few high-profile sports events to go ahead in the city during five months of increasingly violent demonstrations.