The much-anticipated 2014 World Cup got into full swing yesterday with the first full day of action in Brazil.

Mexico and Cameroon opened up proceedings in Natal as the Central Americans came away with a 1-0 victory over their African counterparts, although the scoreline only tells half of the story.

The biggest game of the day - and quite possibly the whole of the group stage - saw a repeat of the 2010 final as Spain and Netherlands went head to head once more, and it didn't disappoint.

Holland ran riot against the defending champions, coming from behind to thrash Vicente del Bosque's men 5-1 and send shockwaves through the football world.

Round one of Group B was then completed by Chile and Australia, who kept the entertainment and goals flowing with an end-to-end encounter that eventually saw the South Americans run out 3-1 winners.

After such an absorbing trio of matches, Sports Mole takes a look at what we learned from day two of the 2014 FIFA World Cup.

If ever there was an illustration of a team being able to beat anyone on their day, this was it. Netherlands went into this tournament with almost unprecedented low levels of expectation, at least in recent times. The outlook was bleak in Holland, where the media were highly sceptical whether they would emerge from a group involving Spain and Chile, as well as expected whipping boys Australia.

Such pessimism is strange considering they reached the final in South Africa four years ago, but the Dutch were more expectant of a repeat of their dismal performance in Euro 2012 than their brush with glory in South Africa. How wrong they were. Netherlands were sensational in their opening match, blowing the mighty Spain away with a second-half performance that will go down as one of the greatest in World Cup history.

Robin van Persie's spectacular diving header shortly before the interval ensured that the Dutch went into the halfway stage all square, and from the moment they re-emerged from the tunnel there was only one winner. Holland were faster, stronger, hungrier and simply better than the defending champions on their way to an astounding 5-1 victory.

Van Persie and Arjen Robben both notched braces in the win and, with such a talented duo in attack, it is impossible to write the Dutch off this year. Daley Blind and Ron Vlaar, amongst others, had the game of their lives - rubbishing pre-tournament suggestions that Holland's defence would be a glaring weak point.

Netherlands must be aware that, emphatic as it was, they still only have three points from the win. They have a habit of starting tournaments in style before fizzling out in the latter stages, so maintaining that level of performance is key. If they can do that, they can beat any other side in the competition this year and could even go on to achieve something the likes of Johan Cruyff, Johan Neeskens, Marco van Basten and Ruud Gullit never managed - winning the World Cup.

In many ways it was hard to watch a team as talented as Spain be dismantled in such a way. The undoubted kings of world football over the past six years, La Roja found themselves humbled and humiliated like never before as they were powerless to resist a majestic Netherlands from scoring almost at will.

Their performance was personified by that of Iker Casillas, for so long the golden boy of Spanish football and a man considered as undroppable from the national team as he once was at Real Madrid. Yet the most experienced player at these finals and the man who held the World Cup aloft following victory over the Dutch four years ago had arguably the worst of his 155 outings for Spain yesterday.

The 33-year-old found himself in no man's land for Holland's first as Van Persie looped a sublime diving header over him and into the net, while he also flapped at a cross for the third Dutch goal - although he may justifiably feel aggrieved with not being awarded a free kick. His night hit its nadir when he was caught in possession by Van Persie to make it 4-1, while Robben seemed to be toying with one of the most decorated players in history when he added the fifth.

Casillas's display wasn't the only poor one yesterday for Spain, but it was representative of the old guard struggling. Last year's defeat to Brazil in the final of the Confederations Cup brought hushed suggestions that the golden generation could be on the way out, while Barcelona's relative struggles last season only served to add credence to such sacrosanct whispers.

Just as Holland can't afford to get too carried away with the win, Spain shouldn't be too distraught with the defeat. However, the manner of the mauling threatens to obliterate the aura surrounding this great Spanish side, and suddenly Wednesday's match against Chile is a must-win encounter for Del Bosque's men. With the South Americans impressing at times in their opening match, that is anything but a gimme for a Spain side that will undoubtedly be rocked.

It is fair to say that the officials didn't get off to the best start when Brazil controversially beat Croatia in the opening match of the tournament on Thursday, and questions over the quality of refereeing were once again raised during Mexico's victory over Cameroon.

This time it wasn't the man in the middle who came under heavy scrutiny, rather the linesman who disallowed two perfectly good Mexican goals in the first half. The first decision saw Hector Herrera shape a lovely cross into the box that Giovani dos Santos converted from close range having timed his run to perfection and got away from his marker. His celebrations were cut short, however, when he wheeled away to see the flag incorrectly raised.

It was deja-vu less than 20 minutes later as once again Giovani span away in ecstasy having prodded his side seemingly into the lead from close range, only for the linesman's flag to once again halt the celebrations. The second decision was even worse than the first, with the Villarreal striker adjudged to have been offside despite the ball flicking off a Cameroonian head from a corner.

Ignoring, for one second, that it fairly clearly did come off the head of Eric Maxim Choupo-Moting, the goal probably should have stood even if it had come off a Mexican last. Giovani looked to be in line with the last defender, who had vacated his position on the post to come forward. The former Tottenham Hotspur man was livid when he saw his dreams of a World Cup goal taken away from him yet again by an incorrect decision.

Justice finally prevailed in the second half as the Mexicans got the winning goal with half an hour remaining, but it was the officials who dominated the headlines from the game. With such a promising and exciting start to the World Cup, it is a shame that so much of the focus has been on the standard of officiating.

This one may be a little premature considering we have only seen two of the eight groups involved in the tournament, but round one of Group B is going to take some beating. It was earmarked as potentially the best group with heavyweights Spain, Netherlands and Chile all in the mix, as well as the lowest-ranked team in the competition, Australia.

However, even the most optimistic of us couldn't have imagined the football feast we were treated to by those four teams yesterday. Spain and Holland kicked things off in style with a match for the ages that saw the Dutch exact cold and brutal revenge on La Roja for their World Cup final defeat four years previously.

The challenge of following that match was an unenviable job, but Chile and Australia gave it a mighty good go. It looked like the South Americans could run away with it when they scored twice in quick succession to take an early 2-0 lead, but Australia - lead by the effervescent Tim Cahill - fought back brilliantly.

The Socceroos pulled a goal back with the most trademark Cahill header that you could wish to see, and they can justifiably claim to have been the better side in the second half. A draw would not have been unkind on them, but in their attempts to push for an equaliser Chile added a third late on to add gloss to a very close, but very entertaining match.

Of course, we still have some mouth-watering clashes to come. Group D contains England, Italy, Uruguay and Costa Rica, while Group G can boast Germany, Portugal, Ghana and the United States, but can any of them top the entertainment provided by Group B so far? If so, we are in for a treat.

Two days and four matches down, and this World Cup is already shaping up to be one of the best ever. The prospect of it being in Brazil - the greatest World Cup nation - was always going to make it extra-special and, after an underwhelming tournament in South Africa four years ago, this one has certainly not disappointed so far.

We have already seen bagfuls of controversy, drama and goals, and we're only just getting started. Every match thus far has thrown up intriguing talking points and been an entertaining spectacle for the neutral, with 15 goals coming in the opening four games.

There may not be a bigger story all World Cup than Spain being hammered by the Dutch yesterday, while Australia almost supplied another early shock with a fine display against Chile last night. Mexico and Cameroon may have only mustered one goal between them, but they played out an entertaining 90 minutes that saw plenty of goalmouth action.

With 60 matches still to come and the likes of Lionel Messi, Cristiano Ronaldo and Luis Suarez still to grace the World Cup pitches, things could could even better over the coming month.