Korean players react to their 11-10 penalty shootout loss to Indonesia in the quarterfinals at the Asian Football Confederation U-23 Asian Cup at Abdullah bin Khalifa Stadium in Doha, April 25, in this photo provided by the Korea Football Association. Yonhap

For the first time in 40 years, Korea will not compete in an Olympic men's football tournament.

And the young Taegeuk Warriors only have themselves to blame, after a poor defensive effort and lack of discipline proved costly in the Asian qualifying tournament Thursday night in Qatar.

Korea fell to Indonesia 11-10 on penalties in the quarterfinals of the Asian Football Confederation (AFC) U-23 Asian Cup at Abdullah bin Khalifa Stadium in Doha.

Korea had to make it to at least the semifinals to have a shot at extending their Olympic appearance streak to 10, dating to 1988.

This year's U-23 Asian Cup doubles as the AFC qualifiers for the Paris Olympics. Only the top three teams — the two finalists and the winner of the third-place contest — will grab their tickets to Paris, while the fourth-place team will face Guinea in a playoff later.

Coached by Hwang Sun-hong, Korea played their worst match of the tournament at the most inopportune time Thursday against what pundits considered an underdog team coached by Korean-born Shin Tae-yong.

After winning all three group-stage matches without conceding a goal, Korea gave up two goals in the first half against Indonesia, both scored by forward Rafael Struick.

Struick's second goal, which broke a 1-1 deadlock during first-half added time, could have been prevented with better defending.

Ivan Jenner sent a Hail Mary of a long pass from his own half toward the box. The ball took a hop just outside the area as Struick chased it down, with defenders Lee Kang-hee and Cho Hyun-taek on either side.

Both Lee and Cho couldn't quite track the flight of the ball. And as Lee tried to block Struick instead of trying to clear the ball out of harm's way, the Indonesia forward danced past him and slotted the ball home past goalkeeper Baek Jong-bum.

Indonesia controlled the run of play in the first half, holding a 7-1 advantage in shot attempts while winning midfield battles with effective press and gap control. Their attackers flashed some skills in making quick passes in tight areas to relieve Korea's pressure.

Hwang brought Lee Young-jun, Korea's leading scorer in Qatar with three goals in two matches, off the bench to begin the second half, but the forward took himself out of the match less than a half-hour later with a costly foul.

Korean players react to their 11-10 penalty shootout loss to Indonesia in the quarterfinals at the Asian Football Confederation U-23 Asian Cup at Abdullah bin Khalifa Stadium in Doha, April 25, in this photo provided by the Korea Football Association. Yonhap

While applying some high pressure, Lee collided with defender Justin Hubner deep in the Indonesia zone, and the contact came after the ball had left Hubner.

Lee was initially cautioned, but a video assistant referee (VAR) review upgraded it to a straight red card. Replays showed that Lee had stepped on Hubner's right ankle on the play, and the unnecessary foul cost Korea their most lethal goal scorer.

Korea rallied to level the score in the 84th minute with Jeong Sang-bin's strike on a counter break. In extra time, though, Korea couldn't overcome their man disadvantage, and they were lucky to send the match to penalties.

During the extra session, Hwang was shown the door after arguing with referee Shaun Evans.

Koreans almost pulled off a miraculous win in the shootout without their head coach on hand, after Baek stopped Hubner, Indonesia's fifth kicker. However, a VAR review ruled that Baek had moved both feet away from the goal line before Hubner took his shot. Given the retake, Hubner scored to keep the shootout going.

Korea's 12th kicker, Lee Kang-hee, was denied by Ernando Ari, and it set the stage for Pratama Arhan's heroics as Indonesia's final kicker.

Arhan beat Baek to the bottom right corner to send Korea packing, with plenty of soul-searching on the horizon.

Indonesia had 21 shot attempts to just eight by Korea and also won the possession battle by a 53-47 margin.

The elimination will leave a black mark on Hwang's coaching resume.

The 55-year-old has been coaching the under-23 national team since September 2021, with the Korea Football Association (KFA) putting him in charge of leading the country at the 2022 Asian Games and potentially the 2024 Olympics.

Hwang has had an up-and-down tenure. Korea lost to Japan 3-0 in the quarterfinals of the 2022 AFC U-23 Asian Cup, Hwang's first major competition, even though Japan had mostly fielded players who were 19, 20 and 21 years old.

Korean players react to their 11-10 penalty shootout loss to Indonesia in the quarterfinals at the Asian Football Confederation U-23 Asian Cup at Abdullah bin Khalifa Stadium in Doha, April 25, in this photo provided by the Korea Football Association. Yonhap

Hwang redeemed himself by leading Korea to the gold medal at the Asian Games, postponed by a year to 2023, and beating Japan in the final to do so.

Hwang also stepped in admirably as a caretaker boss for the senior national team for two World Cup qualifying matches in March, with the KFA still searching for a full-time replacement for Jurgen Klinsmann.

Korea had a win and a draw against Thailand, and earned glowing reviews from the KFA brass for his leadership. The KFA acknowledged earlier this month that Hwang is one of 11 candidates for the senior team vacancy.

The unceremonious exit from the Olympic qualifiers, though, likely has dealt a big blow to Hwang's much-acclaimed leadership.

There were some mitigating factors at work for Hwang. He originally called up five players based in overseas leagues, but three of them — Celtic forward Yang Hyun-jun, Brentford defender Kim Ji-soo and Stoke City midfielder Bae Jun-ho — did not ultimately join the team. Because this AFC tournament isn't on the FIFA international match calendar, clubs were not obliged to release their Korean players.

The playmaking chops of Bae and Yang could have diversified the team's offensive process, while Kim could have been a stabilizing force on the back end.

The compromised Korea went through the group stage with three straight clean-sheet victories but then ran into a wall in the first knockout match.

Hwang is signed through the end of the Olympics, but with Korea not going to Paris, his time with the U-23 squad will likely come to an end. (Yonhap)