The Bafana Bafana, playing at the tournament for the first time since they hosted it in 2010, were widely written off after their 2-0 loss to Group A winners Mexico.
But they battled to a draw against the Czech Republic and came out on top of what was effectively a shootout with South Korea for second place in Monterrey, thanks to Thapelo Maseko’s second-half strike.
South Korea coach Hong Myung-bo made a shock call by leaving captain Son Heung-min, considered by many to be Asia’s greatest-ever player, out of the starting line-up.
The Asian team started strongly, with stand-in captain Kim Min-jae’s powerful header blocked on the goalline by Aubrey Modiba before Lee Kang-in flashed wide.
South Africa quickly settled, playing with hunger and adventure, but their finishing was wasteful.
They seemed certain to take the lead in the 30th minute when the ball fell to Evidence Makgopa after South Korean goalkeeper Kim Seung-gyu parried Thalente Mbatha’s shot.
But Makgopa could only tamely poke the ball straight at the goalkeeper from close range.
Son came on at the start of the second half, one of three changes made by coach Hong as he sought to change the script.
Early in the second period, Maseko squandered another good opportunity while South Korea forward Oh Hyeon-gyu tested goalkeeper Ronwen Williams at the other end.
As news filtered through from Mexico City that the host nation were leading against the Czech Republic, there was an added sense of urgency.
South Africa seized their moment with Tshepang Moremi crossing to Maseko, who this time kept his cool, firing home inside the near post in the 63rd minute.
South Korea pushed hard in the closing stages but ran out of time, meaning South Africa will face co-hosts Canada in Los Angeles on June 28.
Mexico topped the group with nine points after winning all three of their matches. (AFP)
