"Tomorrow our chances are 30 to 40 percent, Inter 60 to 70, but a miracle comes from one percent so that's a lot compared to 30 or 30," the Asian champions' coach Shin Tae-yong told a news conference on Tuesday.
Shin's opposite number Rafael Benitez exuded a calm at odds with reports before Inter left Italy for the United Arab Emirates that his job hinged on his team winning the tournament.
"I'm tranquil, content and have confidence," said Benitez, under fire after mixed results in his first season in charge of the European champions.
"The good spirit has always been there in the group, even in the most difficult times."
Club president Massimo Moratti suggested last week that Benitez's job depended on Inter's results in the tournament although he has since toned down his stance.
Striker Diego Milito, who has been injured and failed to find the form that brought him Inter's treble-winning goals last season, echoed Benitez's sentiments when he said: "I'm fine, raring to go.
"I'll do whatever I can so we win. If I get to score so much the better but the main thing is to win," added the Argentine, whose goals clinched the Serie A title, Copa Italia and Champions League at the end of last season for the team then coached by Jose Mourinho.
Benitez said Seongnam were a well organised team who work well off the ball and are good with it when in possession.
Shin said his team could not compete with Inter's talented players on an individual basis so team work was paramount.
"We are at a disadvantage one-on-one. The only way we can compete is united with at least two players covering (the likes of Samuel) Eto'o, Milito or (Wesley) Sneijder," he said.
"I can't see the weaknesses in Inter but there is no such thing as a team without problem areas so we are trying to identify them."
Impressive central midfielder Cheon Kwang-jin was injured near the end of the first half of Seongnam's 4-1 win over hosts al-Wahda in their quarter-final but Shin hopes he will recover for the match.
Seongnam could become the first team from outside Europe or South America to reach the final, provided they are not pipped to it by Africa's TP Mazembe in Tuesday night's semi-final against Internacional of Brazil (1600).