It feels like a lifetime ago already, but just a couple of short weeks ago the groups concluded and had people stunned at the way the routes to the final panned out. On one side, you had several of the tournament favourites and heavyweights of international football: Brazil, France, Belgium, Uruguay, Cristiano Ronaldo’s Portugal and Lionel Messi’s Argentina.
The other looked a miraculous opportunity. Nobody had predicted that any of England, Croatia, Denmark, Russia, Sweden would go deep into the tournament. They barely had a quarter-final between them over the last decade in either the Euros or a World Cup. Colombia fared well at the last World Cup but had their talisman James Rodriguez missing going into the knockouts.
Spain as pre-tournament favourites stood out but looked off-colour in stodgy performances against Iran and Morocco in the group stage. When they didn’t shake it off and exited meekly at the hands of the hosts, it was confirmed something special would be happening: the stars had aligned to allow an outsider into the final for the first time since Czechoslovakia in 1962.
In the end, it was to be Croatia lining up at the Luzhniki Stadium for the final, and deservedly so: coming from behind to take all three knockout games into extra time and progress each time, the experience and pedigree of Champions League winners Mario Mandzukic, Ivan Rakitic, and Luka Modric were vital components of their run.
But there will be teams, some of whom were sent home long ago, that will look at Croatia and think how it might have been them.
Here are the key moments that will give fans sleepless nights:
1 VAR haunts Portugal
There's been such little VAR drama in the knockout stages that it's easy to forget how often it would punctuate the football in the group stages. There was no greater spectacle than the multiscreen tension of two simultaneous key moments being decided by VAR.
In Kaliningrad, they came to the right conclusion: judging that Iago Aspas was onside as he cheekily clipped the ball into the Moroccan goal. The linesman flagged, and with the aid of technology was overruled.
Back on the Russian mainland, Portugal weren't so lucky as Cedric Soares was deemed to have handballed inside the penalty area.
While it made contact, it was headed down from a couple of feet away, his hand was tucked inside his body, and it had a real influence on the direction of the ball. But after fervent appeals, the referee looked at several replays and came to the wrong conclusion.
Without VAR, without both moments, and crucially without the referee's mistake against Iran, Portugal would have topped group B and avoided their fate of playing Uruguay.
Having beaten Croatia alongside the assorted mediocrity of Europe to win Euro 2016, they would have fancied their chances of reaching the final on the other side of the draw.
2 England - Belgium: A big goal in an empty game.
Journalists can look to recycle their match previews as England and Belgium play their second meaningless, second-string dead rubber of the World Cup on Saturday: this time in the third-place decider.
Both teams had qualified last time they met. Resting and rotating, both teams looked happy to avoid the tougher tests that counterintuitively came with topping the group - and Roberto Martinez cut a conflicted figure on the touchline as Adnan Januzaj of all people sealed the win for Belgium, bamboozling Danny Rose before sending the ball sailing into the top corner.
In the end, both teams can be relatively satisfied with the consequences: after a humdinger against Japan breathtakingly won in a final counter-attack, Belgium secured one of the greatest results in their history with a win over tournament favourites Brazil.
The draw opened up kindly for England, with Colombia and Sweden eminently beatable before the semi-final.
But what might have happened if that goal never went in, or if Gareth Southgate brought on Kane and really pushed for the equaliser. Switches places, could England have also struggled against the surprise package of Japan? Would they have recorded a famous victory over Brazil? Might Belgium have made it to the semi-finals and coped better against the class of Croatia?
3 Karius, Zidane, Lopetegui: the butterfly effect for Spain.
Despite conceding three goals to a Ronaldo-inspired Portugal, Spain played some stunning football in for the majority of their opener as the muscle memory of what Julen Lopetegui had instilled.
Nobody else played such complete and sophisticated possession football as Spain in the years leading up to this World Cup.
But it soon fell apart, Fernando Hierro was not capable of steadying the ship, and the team couldn't manage themselves. Having toiled against Iran and Morocco, they didn't improve and deserved to exit after a dominant but completely sterile performance against Russia.
It's difficult to imagine they would have played so badly under Lopetegui. Would Zidane have left Real Madrid if they didn't triumph in Kyiv? What if Mohamed Salah hadn't been crushed by Sergio Ramos? What if Loris Karius didn't make such unthinkable mistakes?
What if Mauricio Pochettino hadn't unknowingly ruled himself out of the running, by signing a new contract days before the vacancy? Could Lopetegui not have foreseen the consequences? Did Luis Rubiales really have to sack him?
Did it have to be like this?
4 Argentina's list of regrets: Sampaoli, Perez, Messi.
Looking back, it seems Croatia's 3-0 demolition of Argentina could only have ever gone that way. It was telegraphed from the moment Lionel Messi face-palmed his way through the national anthem.
Especially so after the opening goal, Ante Rebic responding quickly to Willy Caballero's gift to him. The mistake was coming, as was the subsequent capitulation, with nervous energy making Argentina cannibalise themselves.
But it took 60 minutes for the game to break. And before that Enzo Perez was given a golden opportunity as Domagoj Vida's botched clearance gave him a free shot. It went wide.
Argentina recovered against Nigeria in order to qualify for the knockout round, but their fate had been sealed by finishing second. A team this wild, with such gaping holes, could never have come through a run of France-Uruguay-Belgium before a final.
But there were special moments. Messi's gorgeous ball in injury time finding the head of Sergio Aguero in injury time, rattling a France who were indefatigable before and since. Those three incredible touches against Nigeria. That Rojo goal.
Who's to say they couldn't produce such moments against Denmark, Russia, and England? Might they have topped the group if Messi tucked away the penalty against Iceland or Perez took that chance against Croatia?
Might they have given themselves a fighting chance if they stuck with the conservative, safety-approach of Gerardo Martino or Alejandro Sabella? It did take them to three finals in three years.
Was the untamed ideological tinkering of Jorge Sampaoli ever going to work with these players?
Which side will have the most regrets after this World Cup? Let us know in the comments below.
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