Qatar reached the Asian Cup semifinals for the first time after knocking out two-time champion South Korea 1-0 on Friday.
Midfielder Abdelaziz Hatim hit the winner with a left-foot shot from outside the area in the 78th minute.
South Korea's best chance was a minute before the decisive goal when Kim Jin-su hit the post from a free kick.
On Tuesday, Qatar will face defending champion Australia or host the United Arab Emirates. They were playing their quarterfinal late Friday.
Japan and Iran meet in the other semifinal on Monday.
Qatar has notched five straight wins, scoring 12 goals without conceding. After winning Group E, Qatar eliminated Iraq 1-0 for its first knockout-stage victory at the Asian Cup.
South Korea also won its group. Forward Son Heung-min played three games after his late arrival from the English Premier League but didn't score.