The stakes are high for the Group H clash in Porto Alegre, after Algeria conceded the lead in a 2-1 loss to Belgium in their opener.
As a result, despite outplaying the highly fancied Belgium at times, Vahid Halilhodzic's side are bottom of the group and will be eliminated if they suffer another loss.
Captain Madjid Bougherra has moved on quickly from the first-up defeat though, and expects a different sort of challenge against South Korea – who played out a 1-1 draw against Russia in their first match at the showpiece.
"It is true that it was difficult after our defeat against Belgium, but we quickly turned the page because that's the competition," Bougherra is quoted by Algerian football website Competition .
"It must be said that what has comforted us, is the fact that everyone can still qualify because we still have two games.
"We can still qualify because we have the quality. I am confident.
"I know the tempo will be different and the style of game too, because we also have to face a different team."
Midfield star Sofiane Feghouli – who plays his club football for Valencia – scored Algeria's first World Cup goal in 28 years against Belgium.
But his first-half penalty eventually amounted to nothing after Marouane Fellaini and Dries Mertens struck in the last 20 minutes.
Halilhodzic felt his players lacked fitness in the closing stages and as a result, is expected to make changes to his side.
"I have told my players that they should not be ashamed of themselves. But this game against Korea is now the decider," he said.
The second-lowest ranked team at the tournament, behind only Australia, South Korea could count themselves unlucky for not taking all three points against the Russians.
They controlled the first half before Lee Keun-ho's effort - inexplicably parried into his own net by Igor Akinfeev - gave them a 68th-minute lead, but substitute Aleksandr Kerzhakov's goal ensured both sides shared the spoils.
It could have been a different story if Bayer Leverkusen's Son Heung-min had taken his shooting boots with him to Cuiaba.
Son, the best player on the pitch and a constant threat, wasted several opportunities and will be keen to make his mark on this clash.
He also knows the importance of nullifying Feghouli, though, and feels it will be crucial.
He said: "Feghouli showed great form with Valencia this season and proved to be a threat on the field. We have to make sure he doesn't become a threat (on this occasion)."
With a clash against likely group winners Belgium still to come, South Korea know victory is almost essential.
But that will not come easy against an Algeria side fighting desperately to stay in the tournament.
