Joachim Loew is facing the biggest crisis of his 12-year reign © AFP Joachim Loew is facing the biggest crisis of his 12-year reign as Germany coach after the holders slipped to a shock defeat against Mexico in their World Cup opener in Russia. Germany are licking their wounds after slumping 1-0 to a Hirving Lozano strike in Moscow’s Luzhniki Stadium — their first defeat in their opening game of a World Cup since 1982. “We won’t fall apart,” insisted Loew, but that is exactly what his defence did in the first-half. Loew is under contract with the German Football Association (DFB) until 2022, but Sunday’s result tarnishes the glittering reputation of the 2014 World Cup-winning coach. “I have not seen the German team so weak at a big tournament for a long time,” said West Germany’s 1990 World Cup-winning captain Lothar Matthaeus.”Almost everything was missing. There were concentration errors, unnecessary bad passes and also the attitude was not there.”Loew has been heavily criticised in Germany for his tactics and keeping faith in under-performing players, especially Sami Khedira and Mesut Ozil.The decision to leave Manchester City starlet Leroy Sane out of the squad after a dazzling season for the Premier…