Mexico's Hirving Lozano celebrates after scoring the opening goal during the group F match between Germany and Mexico at the 2018 soccer World Cup in the Luzhniki Stadium in Moscow, Russia, Sunday, June 17, 2018.
"In the first half we played very badly", Loew said. "It's a situation we're not used to at all".
Kroos agreed with Hummels that Germany now must win their remaining Group F games against Sweden in Sochi next Saturday and against South Korea in Kazan on Jun 27 to be sure of progressing. "We had a couple of shots but it seemed jinxed, sometimes they were too quick in finishing, didn't keep their cool".
Germany kept asking Mexico questions but El Tri's rearguard continued to find answers. "The team has enough experience to deal with it and we will rise again". And there is plenty of historical precedent for teams going on to do well after losing an opening game.
"It will not happen to us", he said when asked whether Germany would fall in the group stage.
But with pressure now mounting and some veiled criticism from his players, including Marco Reus, who said he had been told weeks ago he would not be starting the game despite his current fine form, Loew knows he must deliver. "We have every opportunity to correct things, but we have to make things right".
The champions went into the tournament on the back of a hard build-up, as Manuel Neuer had been out injured for practically the whole season, while Mesut Ozil started despite controversy for posing with the President of Turkey. 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.
Jerome Boateng's build-up to the finals was also hampered by a groin injury, but the Bayern Munich centre-back was on the alert inside 60 seconds to thrust himself desperately in front of a Lozano effort.
After a remarkably open start, Mexico struck the decisive blow 10 minutes before half-time after Sami Khedira lost possession in the opposition half. 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.
The ex-Manchester United and Everton player was on co-commentary for BBC's coverage of Germany 0-1 Mexico and had varying opinions on Ozil. "We will make it (out of the group)".
"It's great to start on the right foot when you are playing against the reigning world champions".
Germany nearly hit back immediately, however, when a Toni Kroos free kick was deflected onto the crossbar by Mexican goalie Guillermo Ochoa.
One desperate last attack then had Neuer come up for a corner before Mexico closed out an unforgettable triumph.
Mexico coach Juan Carlos Osorio has spotted a weakness in Germany's defense.
"We played with bravery when it was needed and defended with all our hearts, I think we need to give the credit where it's due and that's to the players".