The top two sides in the group clash in Ulsan on Tuesday, while Uzbekistan host Qatar looking for a big win to sneak in ahead of the Iranians in the final round of matches.
In Group B, Australia are in the driving seat for the second automatic berth and will seal a third successive World Cup appearance with victory over Iraq. Japan have already booked their spot in Brazil as group winners.
South Korea, on 14 points, could still take one of Group A's two automatic berths even if they lose to Iran but coach Choi Kang-hee has ensured Tuesday's clash will not lack intensity.
In comments that infuriated counterpart Carlos Queiroz, Choi said he wanted revenge for October's 1-0 defeat in Tehran where his team were "badly treated".
"The manners they showed were not good ... they were not hospitable. Aside from who makes it to the World Cup, I would like to beat Iran no matter what," Choi told reporters after his side's 1-0 win against Uzbekistan on Tuesday.
"Honestly, I dislike Iran more (than Uzbekistan). I hope Uzbekistan make it to the World Cup."
Iran, who beat Lebanon 4-0 on Tuesday, have 13 points while Uzbekistan have 11.
Choi's comments did not go down well with Queiroz, who wanted an apology from the South Korean coach.
"Choi should apologise to the Iranian people," the Portuguese told reporters upon arrival in Seoul.
"He said the Korean team was badly treated in Iran but we gave the best treatment available. He humiliated the Iranian citizens."
The war of words escalated after the former Real Madrid coach accused the Koreans of not pushing harder for a bigger victory against the Uzbeks.
"I will buy an Uzbek uniform and give it to Choi as a present," the Iran boss quipped.
Despite the heightened tensions, a draw in Ulsan should be enough to secure automatic qualification for both teams at the soccer showpiece in Brazil as Iran have a superior goal difference to the Uzbeks.
The two third-place finishers in the Asian qualifying groups will face off over two legs with the winners taking on a South American side in two matches for a berth in Brazil.
The Uzbeks' best chance of snatching an automatic berth will be to beat Qatar and hope Korea defeat Iran.
"Nothing has been lost, we still have a chance," Uzbekistan coach Mirjalol Kasimov said after an own goal by Akmal Shorakhmedov just before halftime handed the Koreans victory in their match on Tuesday.
"I really think Korea will win against Iran on June 18 and we will also play well against Qatar and will qualify for the World Cup."
- Sports & Recreation