Saturday was no different, except their route to victory in a key World Cup group game at Russian Federation 2018 was anything but simple for the four-time world champions.
At halftime Germany trailed Sweden 1-0 following Ola Toivonen's sensational finish and were 45 minutes away from a humiliating group stage exit from the World Cup.
Hernandez added the second in the 66th, scoring his 50th goal for Mexico.
Nonetheless, Mexico did double their lead in the 66th minute with a counterattack that brought back memories of their victor against Germany.
But Korea had chances and the momentum of the game turned on another penalty, awarded against Jang Hyun Soo for a blatant handball and converted by Vela.
Vela nearly turned provider two minutes later with a neat ball into Layun, but the former Watford man lashed his effort over from close range. Coach Juan Carlos Osorio insisted that his team would not be complacent, however, underlining South Korea's tactical nous.
Ki Sung-yueng was the next to test Mexico's resolve, stinging the palms of Guillermo Ochoa with a rasping first-time strike. It looked like it could possibly work in moments, but this South Korea side needed to provide more against a Mexican collective that is really clicking and not reliant on any one individual.
Hernandez would not be denied again, though, the West Ham striker making no mistake in drilling in his landmark goal to send the raucous Mexican crowd into raptures.
South Korean forward Son Heung-min scored a scintillating consolation goal in injury time but it was too little too late for the East Asian nation, which now can not qualify for the first knockout stage of the tournament. But the squad have stuck together and built a competitive outfit for the World Cup. - 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.
Things are going very well for El Tri, who recorded consecutive wins at a World Cup for the first time since 2002, and are now a virtual lock to reach the round of 16.
Mexico so far is one of the teams that has a ideal run in the campaign and has conceded just one goa.