The criticism of Mexico's national team heading into the World Cup was loud and scathing.
The momentum Mexico can build with another win might carry El Tri deep into the 2018 FIFA World Cup. Mexico can secure a place in the Round of 16 with a win over South Korea, which must avoid defeat in order to have any chance of reaching the knockout stage of the tournament.
And with 10 minutes to go, Boateng received a second yellow card, reducing Germany team to 10 men and leaving them potentially without either first choice central defender for their must-win match against South Korea, with Mats Hummels suffering from a neck injury.
South Korea threatened again nine minutes later, Son breaking clear of Mexico's line before letting rip with a low drive that Hector Moreno did well to keep out.
Mexico will now have its eyes on Sweden and Germany. A volley from Vela skimmed the bar minutes later.
Hernandez was on the end of a lightning break that bore all the hallmarks of the team's goal against Germany, cutting inside from the left and bobbling the ball past Cho for his 50th worldwide goal.
Ki Sung-yueng was the next to test Mexico's resolve, stinging the palms of Guillermo Ochoa with a rasping first-time strike.
"We didn't listen to the criticism", said Javier Hernandez, one of the scorers against South Korea.
This may have only been a penalty goal for Vela, but it felt like redemption; a reconnection with Mexico fans who had shunned him after he rejected a chance to play for the team in Brazil in 2014, when his career was absolutely on a high. Son Heung-min pulled one back for South Korea in stoppage time with a spectacular left-foot strike from outside the area.
- South Korea has lost its last four World Cup matches, tied for its worst losing run at the World Cup (it also lost four straight between 1986 and 1990). - In the first half, Son Heung-min had six shots (including blocked attempts) - more than South Korea managed in its entire first match against Sweden.