Germany's 1-0 loss to Mexico was a shock scoreline, but the history of the tournament shows World Cup holders often struggle under the pressure of being champions.
Hirving Lozano's fine first-half finish gave Mexico one of the most famous results in the country's footballing history in Moscow on Sunday.
Germany will still be expected to recover and progress from Group F, but Joachim Low's side will have to perform much better in their remaining games against Sweden and South Korea.
The last three World Cup holders have all failed to win the first game of their defence. We have picked out five of the worst performances from defending champions.
3 - This is the third consecutive World Cup in which the reigning champion has failed to win their opening match – Italy drew 1-1 with Paraguay in 2010, while Spain lost 5-1 against the Netherlands in 2014. Hangover.#GER #WorldCup pic.twitter.com/1hNQRlJY5l— OptaJoe (@OptaJoe) June 17, 2018
SPAIN 1 NETHERLANDS 5 – 2014
Having won three major tournaments in a row, many expected Spain to continue that sequence of success when they headed to Brazil as world champions four years ago. But they put in a disastrous performance in their opening match, losing 5-1 to Netherlands in a game that will be remembered for a stunning flying header scored by Robin van Persie.
Spain went on to lose against Chile in their next match too, meaning they were eliminated before even playing their final fixture. A much-changed XI restored some semblance of pride by beating Australia, but the damage had been done.
ITALY 1 PARAGUAY 1 – 2010
Champions in 2006 having beaten France on penalties in the final, Italy also struggled under the spotlight when they came up against a stubborn Paraguay outfit in Cape Town. Marcello Lippi's side were without key midfielder Andrea Pirlo due to injury and his absence was keenly felt, Antolin Alcaraz heading Paraguay ahead. Luckily for Italy they were handed an equaliser when a mistake from goalkeeper Justo Villar enabled Daniele De Rossi to claim a point.
Following that opening flop, Italy drew with New Zealand - again having to come from behind - before losing to Slovakia, finishing bottom of what had appeared on paper to be a very simple group.
ARGENTINA 0 CAMEROON 1 – 1990
Diego Maradona inspired Argentina to glory in 1986 but he was helpless as his side were beaten 1-0 by Cameroon in the first game of their title defence four years later in Milan. Francois Omam-Biyik scored one of the most famous goals in African football history to win the match.
Argentina squeezed through - they qualified as one of the best third-placed teams thanks mainly to a 2-0 defeat of the Soviet Union - and made it all the way to the final despite their sloppy start, losing 1-0 to West Germany in Rome.
WEST GERMANY 0 POLAND 0 – 1978
Heading back to the World Cup hosted by Argentina in 1978, West Germany were unable to get off to a winning start when they were held to a goalless draw by Poland in Buenos Aires.
Current Poland coach Adam Nawalka was in the side that frustrated West Germany. They qualified from the group stage but exited after a 3-2 loss to Austria in the next phase.
BRAZIL 0 YUGOSLAVIA 0 – 1974
Brazil's goalless draw against Yugoslavia at the 1974 World Cup put them on the back foot after just one game. The Selecao side of 1970 is regarded as one of the greatest ever football teams, but despite boasting names such as Rivelino and Jairzinho in their XI four years later, there was no way through the Yugoslavia back line.
Brazil also suffered a 0-0 draw against Scotland but beating Zaire ensured they progressed to the second group stage, from which they had to settle for a spot in the third place pay-off.
|Southgate named honorary Yorkshireman|
|Nicky Butt: Manchester United low on confidence|
|Sissoko: Dembele criticism overblown|
|Thibodeau discusses Butler trade: We thought this was the best deal for us|
|Acuna, Ohtani win rookie of the year awards|
|LeBron James on Lakers’ early season struggles: ‘I almost cracked’|
|Welbeck has successful second operation on broken ankle|
|UEFA warns FFP cases can be reopened based on ´new information´|
|Foakes to keep England place for second Test|
|WATCH: Rooney looking sharp in England training return|
|Mbappe: Money in football is truly indecent|
|Djokovic back to brilliant best as Isner is beaten|
|Celta Vigo replace Mohamed with Cardoso after Real Madrid defeat|
|Joshua intrigued by Usyk, says Hearn|
|Ibrahimovic beats Rooney to MLS Newcomer award|
|Rams WR Kupp out for season with torn ACL|
|Sturridge denies ever gambling on football following FA charge|
|Koeman understands De Ligt´s Eredivisie frustrations|
|Jimmy Butler trade: 76ers acquire Timberwolves star in blockbuster deal|
|´Improve your attitude´ - Deschamps issues Dembele warning|
|Sturridge charged with misconduct over alleged breach of betting rules|
|Saints sign Marshall following Bryant injury|
|Mendy suffers knee injury, leaves France squad with Lacazette|
|Zverev beats Cilic in error-strewn London battle|
|Rafinha replaces injured Casemiro in Brazil squad|
|´One-dimensional´ Australia batsmen need work before World Cup - Finch|
|Mancini keen to work with ´incredibly gifted´ Tonali|
|Italian manager of the year Allegri targets long Juve stay|
|Injured Lee departs as Wales prepare squad for Tonga|
|Conte content to wait until June for coaching return|
|Etzebeth set to return, Whiteley a doubt for Scotland Test|
|In-form Verstappen does not need distractions from 2019 challenge|
|FA asks Guardiola to explain Manchester derby referee comments|
|LaLiga MVP Messi hopes the division stays wide open|
|Murray and Henshaw out of All Blacks Test|
|Injured Man Utd duo Pogba and Martial drop out of France squad|
|Modric cannot always be the best - Dalic|
|Very troubling times - LeBron James alarmed by gun violence|
|Bayern confirm Ribery ´altercation´ with reporter|
|Madrid hit by injuries to Nacho and Casemiro|
|Record-breaking Mushfiqur torments Zimbabwe|
|Spartak Moscow appoint Oleg Kononov|
|Rooney predicts ´exciting time´ after being named in MLS Best XI|
|Former England call-up Graham replaces Thomson in Scotland squad|
|Slater and Thurston among Queensland greats to join Maroons staff|
|Rapana set for six months out after shoulder surgery|
|Alves determined to play in the Premier League|
|Rockets GM denies Anthony will be waived|
|Monaco´s plight not Henry´s fault - Silva|
|It´s like the FBI came - River assistant unable to talk to Gallardo during final|
|Norman says Washington home crowds ´just don´t really care´|
|Bucks beat Nuggets to finish gruelling schedule stretch|
|Madrid ´very happy´ with Solari, says Butragueno|
|Titans stun Patriots, Browns upset Falcons|
|Browns´ Chubb relishes record-breaking performance: It definitely is very special|
|MLS Review: Red Bulls, Atlanta to meet in conference finals|
|Neymar wants more from perfect PSG|
|Higuain is feeling a lot of pressure – Gattuso|
|I didn´t insult anyone, says apologetic Higuain|
|Allegri delighted with Juventus response|
|Kyle Busch wins at Phoenix as Harvick, Truex qualify for Championship 4|
|WATCH: Highlights of thrilling Boca-River Copa Libertadores final|
|PSG coach Tuchel demands more despite Monaco thrashing|
|Boca missed too many chances, rues Schelotto|
|Solari remains tight-lipped on Real Madrid future|
|Hamilton not surprised by Verstappen-Ocon collision|
|Ronaldo fires Juventus to Serie A record|
|Higuain did nothing serious - Ronaldo hopes Milan striker avoids ban|
|Solari completes perfect Real Madrid audition with fourth straight win|
|Verstappen ordered to do public service after Ocon scuffle|