1: POSSESSION DOES NOT PAY FOR BIG TEAMS... YET.
What did Iceland, Mexico and Portugal's sensational opening day results have in common?
They were attained by ceding the bulk of possession to technically superior opposition (Argentina, Germany and Spain respectively), battening down the hatches for a rough night while serving up a threat through shrewd and incisive counter-attacks instead.
Growing frustration at their inability to pass their way through led to an all-out offensive flurry, creating perfect conditions for the likes of Cristiano Ronaldo, Mexico goalscorer Hirving Lozano in particular to fly forward at an undermanned defence, leaving their mark on both the game and the opposition.
Indeed, football has displayed a tendency to flicker between possession football fetishism and settling on a realist commitment to defensive security; Barcelona's (and Spain's by extension) successes under Guardiola's much-vaunted tiki-taka system translated to an insistence on keeping the ball on the ground, while the Catalan side's subsequent 7-0 aggregate drubbing by Bayern in the semi-finals of the 2013 Champions League was an counterattacking masterclass which paved the way for a partial gravitation into the arms of a more Mourinho-esque mentality.
As must be quoted somewhere, history is an argument without end and it will be interesting to see where the latest edition of the World Cup leaves tactical trends and ideas in club football.
2: WHO REFEREES THE VARs?
The World Cup has become something of a testing ground for new technology; while the 2014 World Cup saw the novel addition of the humble shaving foam/vanishing spray to the game and goal line technology, this World Cup has seen the full-scale introduction of a Video Assisted Referee (VAR) to a more mixed reception amongst players and punters alike (just ask any Australian for his unbiased take...).
This extra pair of omniscient eyes has made a notable impact so far, providing a clear review of Diego Costa's initial elbow on Pepe that preceded his brilliant solo effort against Portugal, allowing France a controversial penalty against Australia by overruling the referee and correctly awarding Sweden a less-controversial spot-kick to beat South Korea.
However, this has also served to add another subjective agent to complicate the decision-making process. In real terms, this meant that while England's Harry Kane was rugby tackled on two occasions against Tunisia and Christian Pavon of Argentina brought down with a similar degree of contact as Griezmann was against Iceland, Kane's pleas fell on deaf ears while Pavon's claim was expressly rejected by the VAR.
This is despite it having been far more clear-cut than the previous penalty decision, which saw Iceland goalkeeper and part-time movie producer Hannes Halldorsen produce a brilliant save to deny Messi's conversion.
For all the controversies and drama that have and will undoubtedly soon come, it seems that VAR is here to stay.
3: ROUND ONE- RONALDO 3, MESSI 0
It is a sobering reminder of the passage of time that these two modern-day greats may well be faced with their last chance of adding the elusive Jules Rimet trophy to the endless stockpile of club and individual accolades accumulated in their illustrious careers.
As far as the World Cup stakes are concerned, it is advantage Ronaldo as the Portuguese wasted no time in notching a hat-trick against an imperious Spanish national side, of course boasting a strong core of his Real Madrid teammates.
The first was a decisive strike from the penalty spot after his jinking run was unceremoniously halted by Nacho Fernandez; the second from an uncharacteristic blunder from David De Gea following a relatively tame long-range attempt and the third a true moment of unfettered brilliance, as the 5-time Ballon D'Or winner won and curled a free-kick past both wall and keeper to drag his side level in the dying minutes of the game, as an underwhelming Champions League Final performance was all but forgotten.
Messi on the other hand, still bearing the scars of Argentina's Final heartbreak against Germany in 2014, endured a frustrating afternoon against a dogged Iceland, confined to the occasional flash of genius but never truly sparkling to life as he has done on countless occasions for club and country.
4: TAKE A BOW, JAPAN
The significance of 28-year-old Yuya Osako's sensational winner against Colombia is that Japan have become the first Asian side to prevail against a South American outfit in World Cup history.
This comes with the sweetener that they have accomplished this against a team packed to the brim with attacking talent such as Juventus' Juan Cuadrado, Monaco's Radamel Falcao and Bayern Munich/Real Madrid's James Rodriguez, who lit up the tournament back in 2014.
Colombia's cause was certainly not helped by Carlos Sanchez's handball and consequent dismissal, on top of former Manchester United midfielder Shinji Kagawa's calm and collected finish from the spot.
Although Juan Quintero's deceptive free-kick under the Japanese wall pulled his side level, the "Samurai Blue" would always be poised to press home their numerical advantage and eventually did just that, as 1. FC Köln striker Osako headed in a pinpoint delivery from a corner to seal a famous victory for Japan.
5: EVRA AND MARADONA DISAPPOINT
While FIFA's campaigns to tackle institutionalised racism and sexism have come a long way especially since the era of widespread football hooliganism, both Patrice Evra and Diego Maradona showed this week how such attitudes may remain ingrained in and among the game's "finest".
Appearing as a guest panellist on ITV's World Cup show, the left-back was slammed for appearing to patronise England international Eni Aluiko ahead of the Serbia-Costa Rica clash on Sunday by applauding her in-depth analysis.
Meanwhile, Diego Maradona (by no means a stranger to World Cup controversy) invoked criticism by seemingly making a racist gesture towards an Asian fan in Argentina's 1-1 draw with Iceland, despite his side enjoying 78% possession. Suppose there's only so much you can do to cheer yourself up when you also lost the Falklands with 100% possession...