South Korea dropped to Japan 3-2 Saturday to come up short of the Asian men's under-23 football title in Doha.

South Korea blew a 2-0 second-half lead in the final of the the 2016 Asian Football Confederation U-23 Championship, as Japan scored three unanswered goals in a 14-minute span at Abdullah Bin Khalifa Stadium in the Qatari capital.

The tournament also served as the Asian qualification event for the 2016 Summer Games in Rio de Janeiro. Both countries had already secured their Olympic berths by reaching the final, while the third-place Iraq took the other Asian berth.

South Korea had a pair of goals erased by offside calls in the opening moments, before midfielder Kwon Chang-hoon finally put one in that counted.

Left back Sim Sang-min sent a long cross for forward Jin Seong-uk, who headed it down to set up Kwon's volley. Goalkeeper Masatoshi Kushibiki was frozen in his spot as the shot deflected off the left leg of defender Takuya Iwanami.

South Korea scored first in all of their six matches at the tournament. Five of those goals came in the first half.

Jin, making only his second start of the tournament, nearly got in on the act himself in the 36th minute. It was Kwon doing the setup this time, but Jin, after undressing defender Ryosuke Yamanaka, fired it just over the net.

Jin finally scored on in the 47th. Midfielder Lee Chang-min found Jin near the penalty mark with his back to the net, and the forward turned and struck it between the leg of Sei Muroya and into the net to make it 2-0.

South Korea looked to be in cruise control over the next 20 minutes. Midfielder Ryu Seung-woo had a pair of decent chances, shooting one right at Kushibiki on an open look in the 57th and then shooting it just wide of the left post five minutes later.

In the 64th, midfielder Moon Chang-jin missed an open net with a header, after Sim dragged Kushibiki out of the net and sent a looping cross.

Then the pendulum swung the other way in a blink. With the South Koreans seemingly letting their guard down, substitute Takuma Asano cut the deficit in half in the 67th. Shinya Yajima threaded a pass from midfield and Asano deftly flicked it past goalkeeper Kim Dong-jun, who'd charged out to meet the challenge.

Before the South Koreans could regroup, Yajima evened the score in the very next minute, heading in a Yamanaka cross from left.

Jin tried to answer back for South Korea with a curling shot in the 70th, but Kushibiki made a fine diving stop to his left.

Asano put Japan ahead on a breakaway in the 81st. Following a poor clearing attempt in midfield by South Korea, Shoya Nakajima secured the ball and flipped it over to Asano, who sped past defender Yeon Jei-min and fired it past Kim in net.

The shell-shocked South Koreans kept pressing on but failed to recover as they settled for second place.

Losing head coach Shin Tae-yong said the stunning loss will serve as a learning experience for his young players.

"I think we all learned that if we get careless even for a moment over 90 minutes, we will face consequences like this," he said. "The players did their best until the final whistle. The loss is disappointing, but hopefully we will learn from this and do better in Rio."

Shin acknowledged the defense will have to improve for the Olympics.

"I felt no matter how strong our offense may be, we could fall apart suddenly (on defense)," he said. "We need someone who can be the leader on defense. In a tournament like the Olympics, defense is the most important part of the game." (Yonhap)