Khalfan Fahad fired into the far post from in front of an open goal in an inexplicable miss on Monday that cost defending champion Qatar a spot in the Asian Games football quarter-finals.
Ivan Nagaev scored the winner 18 minutes into extra time to lead Uzbekistan to a 1-0 win and a spot in the quarter-finals against South Korea, who thumped China 3-0.
Fahad was in position to score two minutes into extra time after Uzbek goalkeeper Timur Juraev clumsily overran the ball as it entered the area. Seemingly all Fahad had to do was knock it in, but the young midfielder side-footed it into post and back into the field of play.
"It's a bad moment for him. He's a young player and he's got to forget this one," Qatar midfielder Mohamed Sala Elneel said. "If he thinks about it then he can't keep going in football or in his life.
"Every player has to make mistakes. This is a big one, but that's what happens."
In the other match, the South Koreans dominated a hapless Chinese squad in front of a vocal 44,000-strong crowd, opening the scoring in the 19th minute via Kim Jung-woo.
France-based striker Park Chu-young made it 2-0 from a free kick just after the break and Cho Young-cheol adding a third in the 58th.
"We performed well -- we scored an early goal which meant we were going to win," South Korea coach Hong Myung-bo said.
"The Chinese fans who were so strongly supporting China before the match began to support Korea towards the end."
In other matches, Iran beat Malaysia 3-1 and Oman beat Hong Kong 3-0. Those teams will meet in another quarter-final.
On Tuesday, Japan face India, North Korea are against Vietnam, Turkmenistan play Thailand and United Arab Emirates take on Kuwait.