The criticism of Mexico's national team heading into the World Cup was loud and scathing. "It was just noise".
France 1998 saw 18 penalties awarded, but 2018 - already so dominated by debate around the new video officiating technology - looks likely to break that record with over 30 matches still to play.
Mexico were looking to build on their famous victory over the defending champions Germany in the group opener and, after a slow start this weekend, Javier Hernandez headed wide from a free-kick by Hector Moreno.
It's the 50th career worldwide goal for Hernandez, known as "Chicharito".
Carlos Vela stepped up to slot the ball home, sending South Korean goalkeeper Cho Hyun-Woo the wrong way from what was the 14th penalty in 28 games at Russian Federation 2018.
Hernandez added the second in the 66th, scoring his 50th goal for Mexico. "Our talent and hard work have paid off". A win on the final matchday against Sweden would ensure Mexico finishes atop the group, and if Germany beats Sweden on Saturday as expected, a draw would also be enough for El Tri. "We've received a lot of praise, we the team, and we've tried to remain focused".
Son's sublime 20-yard strike into the top-left corner punctured Mexico's defence in the third minute of stoppage time, but it would prove little more than a consolation as South Korea slumped to a second successive defeat.
Mexico relied on keeping possession and long-range shots, with a powerful attempt from Andreas Guardado forcing an athletic save from Jo in the second half.
Mexican fans avoided using a chant, which is considered to be homophobic by Federation Internationale de Football Association, against the opposing goalkeeper. Germany (no points) face Sweden (three) later on Saturday.
South Korea wanted a penalty of their own after the restart when Moon Seon-min's strike clipped Carlos Salcedo's arm, but the referee correctly waved away their appeals.