Park Ji-sung struck eight minutes from time as South Korea salvaged a crucial point against Iran to remain top of World Cup qualifying Group B.
The Koreans had never won on Iranian soil and that record looked unlikely to change when Javad Nekounam put the home side in front with 58 minutes gone at the Azadi Stadium.
But Manchester United midfielder Park pounced on a loose ball to earn a draw for the visitors that keeps them two points ahead of Ali Daei's side, who slipped to third in the group after North Korea beat Saudi Arabia earlier in the day.
Iran began the game seemingly intent on taking the upper hand early and Masoud Shoujaei fired over the bar before Nekounam failed to find the target with a header.
Yeom Ki-hun tested Sayed Mahdi Rahmati with a free-kick as Korea threatened towards the break and the same player saw another set-piece turned behind by the Iran custodian in the 42nd minute before he also kept out Kim Chi-woo's powerful effort.
However, Iran took the lead 13 minutes into the second half when Nekounam's free-kick found the top corner.
Korea went in search of a reply and Lee Keun-ho hit the bar with a header two minutes later before Mohammad Reza Khalatbari worked keeper Lee Woon-jae with a useful effort.
The visitors stepped up the pressure in the final 15 minutes and it paid off late on as another Yeom free-kick was saved by Rahmati but Park was on hand to net the equaliser.