A day earlier, Mexico's Colombian manager Juan Carlos Osorio said he had drummed into his charges that they were not to be overawed by their highly-touted opponents, and with this win, they demonstrated they clearly were not.
The script did not go as planned for the holders as Mexico's young star Hirving Lozano wrote his name into Mexican soccer lore at Moscow's Luzhniki Stadium, scoring a goal in the 35th minute that would prove enough.
The situation did not change after the break, as Juventus midfielder Sami Khedira lost possession, was too slow to track back and Chicharito Hernandez's roll across to Carlos Vela was heavy. He outpaced Jerome Boateng and with a less than flawless pass found Lozano, who controlled the ball, cut inside Mesut Ozil, held off a charging Toni Kroos and slotted past Manuel Neuer.
Germany's preparations ahead of the World Cup were plagued by poor results and controversy, and their problems were magnified in Moscow as they crashed to their first defeat in the opening game of a World Cup since 1982.
"Our motto was play with the love of winning and not the fear of losing", said a delighted Osorio.
"In the first half we played very badly", Loew said.
"But the next game is now more important", he added of Saturday's clash with Sweden.
"Mexico deserved the win", Hummels conceded.
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Antoine Griezmann opened the scoring in the second half with a penalty but Mile Jedinak replied from the spot just four minutes later.
Russian Federation is holding its first time ever edition of the FIFA World Cup, which kicked off in Moscow with a spectacular opening show at the Luzhniki Stadium on the night of June 14.
Those strengths are their attacking game and solid defence and both were painfully missing from their game against the Mexicans, who caught them on the break seemingly at will.
Youngster Julian Brandt almost saved Loew's night in the final minutes when he blasted a shot past Ochoa's right post.
Mexico can dream of going better than a consistent record of reaching the last 16 of the last six World Cups and perhaps of improving on the quarter-final they last reached in 1986.
In the other group F fixture, South Korea will square up against the Swedes at the Nizhny Novgorod stadium. "Our team has experience of dealing with losses, the next match will be decisive and we have to win it".
But their reputation is not what it was.
"We need to focus on our strong points, which we haven't been able to do in our last couple of games". Germany were thoroughly exposed during this transition as pushing bodies upfield left acres of space for the Mexican to run into, and had to run for their lives everytime they broke forward.
The teams were divided into eight groups, with four in each, and the top two from their relevant groups will proceed to the next round, known as the playoffs or the knockout stage, to keep vying for the much-coveted FIFA World Cup Trophy.