Goalkeeper Eiji Kawashima was the hero as Japan reached the Asian Cup final by beating South Korea 3-0 on penalties at Al Gharafa stadium.
South Korea had been celebrating wildly at the end of extra time after defender Hwang Jae-won hammered home an equaliser with just seconds to play to make it 2-2.
But Kawashima saved two spotkicks and saw another sail wide of his post before Yasuyuki Konno scored his kick to put the Samurai Blue in sight of their fourth Asian Cup trophy.
The win in Qatar was the first time Japan had beaten South Korea in six years, and they had earlier fallen 1-0 behind when Ki Sung-yong scored from the penalty spot in the first half.
But Ryoichi Maeda levelled later in the first half, before Hajime Hosogai pounced on a rebound from Keisuke Honda's controversial penalty in the seventh minute of extra-time after a goalless second half.
The Koreans, hunting their first Asian Cup in more than 50 years, grabbed a reprieve when Hwang forced home the ball seconds from the final whistle.
But South Korea blew their lines in the shootout to send Alberto Zaccheroni's Japan into a final with either Australia or Uzbekistan - their fourth final appearance in six tournaments.
The early exchanges of the East Asian derby saw Japan's precise passing moves almost bear fruit as Yasuhito Endo played Yuto Nagatomo behind the Korean defence.
The free-running left back whipped in a cross that Shinji Okazaki powered low towards the corner, but Jung Sungryong dived to his left to claw the ball onto the inside of the post.
South Korea were winning possession through the tenacity of captain Park Ji-sung, whose commitment in the challenge was barely toned down by a yellow card for an elbow on opposing skipper Makoto Hasebe.
Their graft was rewarded on 23 minutes when Konno obstructed Manchester United midfielder Park in the box, with Ki hammering the penalty past Kawashima.
That gave the Korean half of a colourful and noisy East Asian crowd of 16,171 the upper hand in the decibel stakes, and they could have seen their side go two up when Ji Dong-won went on a teasing solo run down the middle before his shot was blocked by Nagatomo.
Some delightful Japanese passing soon gave the Samurai Blue an equaliser.
After a quiet performance in the 3-2 quarter-final win over Qatar, CSKA Moscow midfielder Honda patiently held up play before threading a pass through for Nagatomo, who charged into the box before squaring for Maeda to force the ball into the net.
Honda set up Maeda again a minute before half time, but the Jubilo Iwata striker's chested volley was fired over the bar.
That was the story of the second half, as the Koreans in particular peppered the general area of the goal.
Ji took off on another solo run, but Koo Ja-cheol could only pop the ball into the side netting after latching onto the forward's pass.
It took extra time before the deadlock was broken in Japan's favour via a controversial penalty decision from Saudi referee Khalil Al Ghamdi.
A through-ball to Okazaki saw the Japan striker deliberately bodychecked by Hwang as he charged into the area, but replays showed the original contact was just outside the box.
South Korea's appeals to the linesman were of no avail and after Jung Sungryong saved Honda's kick, Hosogai hared forward to slam the rebound high into the net.
Hwang looked to have gone from zero to hero as he slammed home the last-minute equaliser, but Koo, Lee Yong-rae and Jeong Ho-hong all missed their chances as South Korea extended their long wait for a continental trophy.
