1. Mexico stun Germany - will holders crash out again?
Day four brought the biggest shock of the 2018 World Cup so far, as Mexico ran out 1-0 winners against Germany at the Luzhniki Stadium. El Tri sliced Joachim Low's side apart on the counter-attack and could easily have recorded a bigger victory had they been more decisive with their final pass. The Germans looked laboured and one-paced, with centre-backs Mats Hummels and Jerome Boateng left exposed to fast breaks time and time again.
Three of the last four World Cup holders have been eliminated in the group stage: France in 2002, Italy in 2010 and Spain in 2014. It would still be a major upset if Germany made it four in five, but few saw this result coming.
2. Brazil held by spirited Swiss
Brazil came flying out of the traps against Switzerland in Rostov, and their fast start was rewarded when Philippe Coutinho crashed a superb strike in off the post. The Selecao were expected to cruise to victory at that point, but instead they became surprisingly wasteful in possession and ragged without it.
Switzerland ended the first half the stronger of the two teams, and they were back on level terms soon after the restart when Steven Zuber powered home a header. Tite's side went in search of a second goal but couldn't find it, meaning three of the four pre-tournament favourites - Germany, Spain and Brazil - have failed to record a win in the first round of games.
3. Costa Rica pass surprise package baton to Serbia?
Costa Rica provided the underdog story of the 2014 World Cup, topping the so-called 'group of death' ahead of England, Uruguay and Italy, then beating Greece to reach the last eight for the first time. They were only eliminated on penalties by the Netherlands at the quarter-final stage, but a repeat of that tremendous accomplishment looks highly unlikely four years on.
Los Ticos didn't provide much of an attacking threat against Serbia, who triumphed 1-0 thanks to Aleksandar Kolarov's stunning free-kick. Mladen Krstajic's side would have won by a wider margin had Aleksandar Mitrovic brought his shooting boots, and perhaps they will be this year's surprise package in the same way Costa Rica were in 2014.
4. Southgate looks at bigger picture
England's World Cup campaign gets under way on Monday, with Tunisia providing the opposition at the Volgograd Arena. Manager Gareth Southgate has been looking beyond that clash, though, emphasising the need for his players and staff to embrace the occasion.
"When I have been at World Cups before, whether working with the media or following the games scouting, there is a kind of carnival of football out there that sometimes as a player you don't access and don't feel part of," he said. "We have got to feel that it is a festival of football that you are fully involved in, and look to play as well as we can."
5. Messi reflects on missed penalty
The story of day three in Russia was Lionel Messi's missed penalty, which proved costly as Argentina were held to a 1-1 draw by Iceland. The Barcelona man doesn't have the best of records from 12 yards, and he admitted that the game would have changed had he found the net.
It would have changed the script. It was the advantage," Messi said. "Obviously it hurts me to have missed the penalty. They would have opened a little more and we could have found more spaces. We have the bitterness of not being able to take the three points that we deserved. To start with winning is always important, now we have to think about Croatia."
6. Aluko outshines Evra, who lets himself down
Eni Aluko has been a breath of fresh air as an ITV pundit, delivering insightful information in an accessible manner. It's a shame, then, that a well-researched explanation of Costa Rica's style of play was met in patrionising fashion by Patrice Evra, who decided to clap Aluko and declare: "I think we should leave Henri [Larsson], because she knows about more football than us! I’m really impressed you know."
It's hard to imagine he would have acted in the same way had Aluko been a male pundit.
