An extraordinary row between South Korea and Iran highlights tensions in Asia's final World Cup qualifying group matches, with Australia also urging caution before trying to book their ticket to Brazil.
South Korea's promise to "make life painful" for Iran and to force their captain to cry "tears of blood" have sharply raised the stakes before Tuesday's clash between the Asian giants at Seoul's World Cup stadium.
South Korea, who lead Group A by a point, need only a draw to reach Brazil 2014 but victory for Iran would guarantee their fourth World Cup finals appearance. Third-placed Uzbekistan, two points behind Iran, must win in Qatar to stand any chance of automatic qualification.
In Group B, Australia can join Japan, who have already secured qualification, to Brazil with a win over Iraq in Sydney. Oman, a point behind Australia in third, take on Jordan as they bid to snatch second place from the Socceroos.
But South Korea and Iran, with 11 World Cup appearances between them, have added considerable emotional spice to their meeting with tit-for-tat barbs between their coaches and players.
After Korean boss Choi Kang-Hee's vow to "make life painful" for Iran drew a strong response from their coach Carlos Queiroz and captain Javad Nekounam, the home players launched a fresh salvo.
"I will make him (Nekounam) shed tears of blood," said Germany-based forward Son Heung-Min, while Choi vowed that Queiroz would be watching the World Cup from his home in Portugal.
The dispute follows South Korean accusations of ill-treatment during their visit to Tehran last October, with complaints including visa problems and poor training facilities. In a feisty encounter, South Korea lost 1-0.
"Our players all remember the poor treatment they got (in Tehran). I think we must make life painful for Iran," Choi said last week.
Iran have won 10 of their 26 head-to-head games against nine victories for South Korea, but Team Melli's visits to the Korean Peninsula also include a notorious World Cup qualifier in neighbouring North Korea in 2005.
Home fans hurled bottles and chairs on to the pitch during Iran's 2-0 victory in Pyongyang, and angry spectators blockaded the visiting team inside the stadium afterwards.
Australia will hope for a smoother outing against Iraq, especially after last week's 4-0 drubbing of Jordan put them on the verge of their third successive World Cup.
Iraq, the 2007 Asian Cup champions, are missing captain Younis Mahmoud and influential midfielder Nashat Akram. But Australia's old heads have joined coach Holger Osieck in warning against premature celebrations.
"The manager and the senior players have made sure no one's talking about dancing the samba. Nobody's in Brazil yet," said Australia captain Lucas Neill.
"We need one game, one win. Then we can start thinking about all the dreams coming true."
Time is catching up with the greying Socceroos, with goalkeeper Mark Schwarzer set to be 41 by next year's World Cup, while Neill, striker Tim Cahill and midfielder Mark Bresciano will all be 34.
But the chance to contest a third World Cup together, after reaching the last 16 in 2006 and narrowly failing to go past the group stage in 2010, has proved powerful motivation for the Aussie veterans.
"We really would love to play this World Cup together because it's been such a great adventure being part of the Socceroos for so long," Bresciano said.
"For me personally and some of the other boys, we'd get to play in three World Cups if we get a result on Tuesday so it would be a massive achievement for a lot of us."
The top two teams in Group A and B earn automatic qualification. The two third-placed sides will face each other over two legs in September.
The winner of that will play an intercontinental play-off in November against the fifth-placed team from South American qualifying for the final place at Brazil 2014.