Clear favourites at the London games, Brazil remained unbeaten during the group stage but fought their way back against a 9-man Honduras side in the last eight.
Brazil striker Leandro Damiao was at the double when his team were trailing twice. Along with Leandro's brace, Santos FC sensation Neymar converted a penalty to avoid a huge upset from underdogs Honduras.
South Korea played a gruelling 120-minute quarter-final match to eliminate Team GB from the competition. Stuart Pearce's men bowed out of the Games after losing 5-4 in the penalty shoot-out.
After a nervy and tense clash with Great Britain, coach Myung-Bo Hong's team will be tested yet again after clinching only 1 win against Switzerland in three group matches while the other two ended in scoreless draws against Mexico and Gabon.
But with four wins in a row and three goals in each game for Brazil, the Koreans have to up their game tempo and eye for a major upset. That seems to be a mere impossible task for a team who reached the semis for the time.
However, Mano Menezes' men have gaps to fill in their fragile defence which conceded five goals so far.
Meanwhile, there are no serious injury concerns for Brazil as full back Alex Sandro will be available for selection after suspension while defensive midfielder Sandro could return after his withdrawal minutes before the halftime against Honduras.
After sustaining an exhausting 120 minutes against Team GB, South Korea have few injury worries coming into the last four. Right-back Kim Chang-Soo was withdrawn after injuring his hand while goalkeeper Jung Sung-Ryong is a major doubt.
Although Korea's chances of winning are bleak, they can certainly steal the show if they absorb pressure and burst forward with a counter attack. The Asian giants have to follow the way Honduras and Egypt had fought their way into the game against the Samba Boys.
Both sides are likely to retain the same squad and the winner will play for gold against either Mexico or Japan.
Kick-Off at 00:15 AM IST on 8th August, Old Trafford, Manchester.
Brazil: (4-3-3): Neto-Rafael, Juan, Thiago Silva, Marcelo-Sandro, Romulo, Oscar-Hulk, Damiao, Neymar.
South Korea: (4-4-2): Lee-Oh, Yung, Y Kim, K Kim-B Kim, Ki, Koo, Han-Ji, Park.