The substitute proved decisive in a very tightly contested game.
Neither team dominated the proceeding early in the game as chances were few and far between in front of both goals. Cha Du-Ri was causing problems down the right for Iran and he nearly created a goal with a rampaging run in the 25th minute, but his final ball could not find a red shirt.
Park Ji-Sung was also active in attack and his first chance of the game came moments later when he just could not reach a ball near the byline and apply a finish. South Korea were clearly the better team in the first half hour as they passed the ball around nicely, but were actually struggling to make possession count.
Koo Ja-Cheol went close with a meek header in the 41st minute, when Iran's defence completely misjudged a seemingly harmless situation. Ji Dong-Won had a shot fly over the bar just before half-time for what proved to be the final moment of interest for the first half.
Iran stepped up a gear in the second half and could have found a goal through Gholamreza Rezaei in the 62nd minute when the striker seemed to have been pulled down by Jong-Soo Lee. Three minutes later, however, Dong-Won found himself on the end of a marvelous cross by Du-Ri, but headed disappointingly at Seyed Mehdi Rahmati from just outside the six-yard box.
In the following attack Mohamadreza Khalatbari was granted the ball after a fortunate rebound in the box, but he was too slot to react and Jung Sung-Ryong managed to claim his weak finish. Javad Nekouman went close with a free-kick just before the eighty minute mark and Rezaei wasted two chances in the space of two minutes just before the ninety minute whistle.
The game entered extra time and it seemed that neither team was willing to take any risks. There were no clear-cut chances for either side, but in the one-minute injury time of the first half of extra time Bit-Garam find the opener with a magnificent solo run and finish.
The heartbreaking development of the game left Iran with only fifteen minutes to mount a comeback. They went close through Andranik Teymourian, substitute Massoud Shojaei and Javad Nekouman, but to no avail as the Taegeuk Warriors managed to defend their one-goal lead to the final whistle.
Iran crash out of the Asian Cup, while South Korea will face Japan in the semi-finals of the competition.