Abdelaziz Hatim fired a late winner as Qatar stunned title-chasing South Korea 1-0 to reach the Asian Cup semifinal for the first time on Friday.
South Korea were looking to end 59 years of hurt in the tournament but missed a string of second-half chances in Abu Dhabi before Hatim's hammer blow after 78 minutes.
It took the Koreans until three minutes into the second half to register a shot on target, Hwang Ui-jo forcing a low save from Saad Al-Sheeb from the edge of the box.
Lee Chung-yong then blazed wide and captain Son Heung-min was denied by Al-Sheeb before Kim Jin-su's free kick smacked against the post.
That wastefulness came back to haunt them when Hatim smashed a long-range rocket past goalkeeper Kim Seung-gyu to give the 2022 World Cup hosts a famous victory.
Hwang thought he had equalised two minutes later, only to be given offside — a decision upheld by the video assistant referee.
Qatar's semifinal opponents will be either hosts United Arab Emirates or holders Australia, meeting in Al-Ain later on Friday.