STORY: Crowds of people, including some security personnel, waved the Iranian flag in the city center's Valiasr Square after Iran scored twice after the eighth minute of stoppage time to snatch a 2-0 win.
Iran's win is a boost to their World Cup campaign, giving them a chance of reaching the knockout stage after they were beaten 6-2 by England in their Group B opener.
The Asian team has never got past the group stage at five previous World Cups but Carlos Queiroz's players will now fancy their chances after an impressive display as they punished a Welsh side that was reduced to 10 men late in the second half.
The celebrations in Tehran were a stark contrast to weeks of anti-government protests that have gripped the country after the Sept. 16 death in custody of 22-year-old Kurdish woman Mahsa Amini.
The unrest has posed one of the biggest challenges to Iran's Shi'ite clerical rulers since they came to power in the 1979 Islamic Revolution, with previous bouts of sustained protest eventually being crushed.