Germany had a slew of chances in the final minutes, but could not convert.
Mexico custodian Guillermo Ochoa made a brilliant save to keep out a Toni Kroos free kick in the 35th minute while Germany essentially laid siege to the Mexican penalty area in the final 20 minutes. But with Ochoa standing up to a relentless German attack that got off 25 shots, it was enough to leave Germany without a point one game into a World Cup for the first time in 36 years.
But despite the loss - the first for a German team in a World Cup opener since 1982 - coach Joachim Low remains confident that his side will progress to the knockout stage in Russian Federation.
Mexicans celebrating their win over Germany.
Germany came into Russian Federation 2018 tipped as favorites by many, looking to become the first team to retain the World Cup since Brazil in 1962.
"I think we did not find any solutions in the first half", Kroos said. In the first half we managed to play defensively with a great deal of intelligence and hit them on the counter.
Although Low admitted that his side need to improve, he also insisted that his tactics will remain the same for Germany's remaining matches.
Germany defeated Mexico 4-1 in last year's Confederations Cup while sporting a younger lineup. Javier "Chicharito" Hernandez, who looked shaky early on, sent a long through ball forward for Lozano, racing into the box on the left wing.
They've had an unenviable record of having been knocked out in the round-of-16 in six successive tournaments, but after this famous win, they will surely be looking to at least go a step further in Russian Federation.
Coach Juan Carlos Osorio's bold approach - often leaving three attackers up the pitch even when defending set-pieces - paid off, as celebrating fans in Mexico City caused a minor natural disaster.
"But we will not just break apart now and become headless and do something completely different". In addition to that, they took the trophy home to complete their near flawless run in the tournament.
Hummels felt Germany did not heed the warning of their final warm-up friendly against Saudi Arabia that ended in a tight 2-1 win, their only success in seven matches since the end of the World Cup qualifying campaign a year ago.
"Mexico deserved to win and we made it too easy for them, even though we knew exactly how not to play against them". "We played with bravery when it was needed and we defended with all our hearts".
Twitterati couldn't stop making "wall" jokes after Mexico took down Germany in the opening match.
The last World Cup was a classic example where Mexico led the Netherlands until the 88th minute before conceding two quick fire goals to lose 2-1.