Monday 18 June 2018 09:19, UK
On a day of upsets, set-pieces and yet more questions over VAR, we round up the talking points from day four at the World Cup.
Each day during the tournament, we will be pulling together all the big stories and best reaction right here in a nutshell, so you do not miss a thing.
Here are the highlights from day four at the World Cup...
Germany 0-1 Mexico
Hirving Lozano's first-half winner caused the shock of the World Cup so far as defending champions Germany were beaten in their opening game for only the second time in history.
Joachim Low's side were lethargic and sluggish at times and often caught on the break by their Central American opponents - and deservedly found themselves behind at the break to Lozano's low near-post finish.
Julian Brandt whistled a first-time shot just beyond the post at the other end late on, but Mexico held on for a historic win to leave Germany bottom of group F.
Costa Rica 0-1 Serbia
Aleksandar Kolarov's brilliant second-half free-kick saw Serbia beat Costa Rica 1-0 in their opening Group E contest.
The Serbs won the game thanks to captain Kolarov's wonderful strike 11 minutes into the second half, the third goal from a direct free-kick at this World Cup.
Mladen Krstajic's side held out comfortably thereafter in Samara to get their campaign off to a winning start, with Costa Rica lacking the cutting edge to really threaten their opponents.
Brazil 1-1 Switzerland
Brazil's tournament got off to the perfect start when Philippe Coutinho curled in a stunning opener from outside the box to put them ahead against Switzerland.
They could easily have been three goals to the good by half-time, but the Europeans improved shortly before the break and took that into the second half - where they duly equalised.
There was a hint of controversy about Steven Zuber's header from a corner to level, as he appeared to push defender Miranda in the back - but the Swiss took their slice of luck and kept goalkeeper Yann Sommer relatively untroubled as they held on for a memorable point.
Mexico's Hirving Lozano provided the upset of the tournament so far when his first-half goal put world champions Germany behind in their opening game of the tournament.
A tactical masterclass from boss Juan Carlos Osorio, leaving three men forward and catching Germany on the break, worked to perfection to put underdogs Mexico top of their group.
"I don't know if it's the biggest win in Mexico's history but doubtless it is one of the biggest for sure."
"We will not suffer that fate [of not qualifying]. We will make it to the next round."
"This team shouldn't be burdened with that because they're a fresh group, most of them have very few international caps, so the future is all ahead of them."
We thought this summed up the unusual feeling the German people are experiencing tonight rather well...
And really, it's only fair to include an old friend of Mexico boss Juan Carlos Osorio, with a clue about where he learned it all...
England arrived in Volgograd just over 24 hours ahead of their first game of the tournament against Tunisia, which kicks off on Monday at 7pm.
Manager Gareth Southgate resisted the temptation to put his team through their paces on the pitch in the 45,000-capacity Volgograd Arena, instead finalising their preparations at the Three Lions' training base in Repino before heading south.
Southgate and captain Harry Kane did face the media at the stadium, however, where the manager said he believed his players' youth and, for many, new experiences would act be a help rather than a hindrance during the World Cup.
Injured Belgium defender Vincent Kompany will stay with the squad despite being ruled out for at least another week by injury.
The Manchester City captain was hurt during Belgium's friendly game with Portugal two weeks ago, and will not be fit until at least the final group game with England on June 27.
However, Martinez is confident the 32-year-old will be ready to play a part in the Red Devils' tournament.
"We are not going to use any changes," he said. "Vinny has evolved better than we thought, even though we thought that he could have a good opportunity to be involved in the group phase. Now he has a stronger opportunity."
There is worse news for Russia's Alan Dzagoev, however, who has been ruled out of the rest of Russia's group stage games after injuring his hamstring against Saudi Arabia.
The 28-year-old CSKA Moscow midfielder went off injured in the first half of the 5-0 win - and will see his World Cup over, if the hosts fail to make it out of Group A.
Two England fans have completed an incredible 24,000km cycle from Hampshire to Volgograd for England's Group G opener with Tunisia tomorrow.
Jamie Marriott and Mitchell Jones took their bikes on the tour of their lives across Europe in aid of the Bobby Moore Fund, raising more than £2,000 from their 25-day adventure.
