Anything less than that and the Taegeuk Warriors will be condemned to a group-stage elimination for the third consecutive tournament -- with their last knockout round appearance back in 2010 an increasingly decent memory.
Given the slow start they have made at Qatar 2022, the odds are stacked against the South Koreans.
The task at hand is certainly not lost on them with defender Kim Young-gwon -- speaking at Thursday's pre-match news conference -- admitting: "They (Portugal) have all these talented players. To contain them, we'll have to play as a team, as one unit.
"We played our first two games with passion and we're going to have to show that passion again tomorrow, but we'll also need a bit of luck. If we have all that, we can create a miracle."
It is undeniable that the South Koreans have not been found wanting in the passion stakes, and luck has certainly been a factor. The solitary point from their matches against Uruguay and Ghana could perhaps have been a healthier haul of four had they had better fortune.
But rather than focus on the intangible, perhaps the factors that South Korea should really be counting on are two that could actually have a direct impact on proceedings -- midfielder Hwang In-beom and forward Cho Gue-sung.
Although all the attention leading up to the World Cup was on captain and star man Son Heung-min, the Tottenham man has struggled to exert in his influence on proceedings despite his best efforts -- understandably considering he continues to recover from a facial fracture that required surgery, and the wearing of a protective mask, just last month.
The 24-year-old's headed double against Ghana nearly rescued a point for the Taegeuk Warriors and almost instantly propelled him to prominence, considering he was widely unknown prior to that having spent his entire career to date playing domestically.
While Cho probably would have expected to play a back-up role to Hwang Ui-jo heading into the World Cup, he should now probable impossible for coach Paulo Bento to drop after seizing his opportunity against the Ghanaians.
The Portuguese first-choice centre-back partnership of Ruben Dias and Pepe are far from slouches yet Cho, currently on the books of K League 1 giants Jeonbuk Hyundai Motors, has already shown he has all the physical attributes to do battle with perceived stronger opponents.
Of course, in order for South Korea to create chances for Cho to feed off, they will first need to have possession against a Portugal outfit that do enjoy to hog possession.
That is where someone like Hwang In-beom comes in.
While not exactly the deepest of South Korea's central-midfield trio, with the main duty of breaking up the opposition player falling to Jung Woo-young, Hwang In-beom also weighs in with his fair share of defensive work but is also usually the first man his team turn to in order to initiate a foray forward.
He has already pieced together an admirable campaign in Qatar in spite of his country's failure to pick up a win as yet, and his ability to get South Korea on the front foot against a star-studded Portuguese midfield will be decisive to their chances.
There are others who could easily come into play for South Korea.
Son, for one, is primed for a standout display just as he did four years ago in Russia when the Taegeuk Warriors stunned then-champions Germany 2-0. After a tantalising cameo appearance against Ghana, Lee Kang-in could also influence proceedings should Bento be willing to use him from the start.
There are certainly many factors that could decide whether South Korea can indeed pull off "a miracle" and give themselves the best chance of reaching the Round of 16 at this year's World Cup.
More so than just passion and luck, it could be down to players like Cho Gue-sung and Hwang In-beom.