Vicente del Bosque will have been left dismayed by Spain's 5-1 humiliation at the hands of the Netherlands last week, and Wednesday's fixture against Chile now holds far greater importance for his side.
The South Americans will already have been looked upon as tough opponents prior to that opening display, but this matchup would undo Spain's title defence at the first hurdle should they stumble again.
Chile's 3-1 triumph over Australia, meanwhile, pitches them in second place after Louis van Gaal's men, but the Spanish will be the first true test of La Roja's mettle at this World Cup.
Group B's tale will take a massive turn at the Maracana, and you can find all the viewing details, along with a form guide and a prediction below.
Date: Wednesday, June 18
Time: 8 p.m. BST/3 p.m. ET
The loss to Holland would serve in extinguishing any good form that Spain may have held coming into this World Cup. Before coming to Brazil, the team had lost just once in their last 10 games, but even the reigning world champions look vulnerable after that result.
Chile's late form is similar in that they have suffered just two defeats in their last 16 matches, but the benefit of a three-match winning streak should see them come to Rio de Janeiro as a jovial collective.
Lowe quotes the Spain boss in saying:
We will keep some things the same but we will change others. We are flexible in some aspects of the game but stubborn in others. Nobody should be alarmed by the changes that are made. We will not be singling out anybody. All of the players have our affection and appreciation. We were the ones that brought them here. But above any personal considerations, we have to find solutions for the team.
Rediscovering that team dynamic will be critical after such a disjointed affair last time out, and with the Mail Online confirming David de Gea's absence through injury, it remains in doubt as to whether or not Iker Casillas will start:
It's been a trademark of Chile's lately that when they win, they do so with free-flowing, attacking football. The last time Jorge Sampaoli's men won a game by scoring a sole goal came all the way back in July 2011 against Peru.
Spain will be an unknown quantity for the South Americans, and with Chile having kept just three clean sheets in their last 10 matches, it's certainly foreseeable that Del Bosque's men will net.
These two sides met in September 2013, when matters ended at two goals apiece. A similarly frantic piece of drama could unfold nine months on.
This match has been talked about for some time as one that will come down to a matter of tactics: Spain's brand of possession-based football meets a more intense, counter-based form in Chile, setting the scene for fireworks.
However, a substantial factor to consider before the melee relates to the mental, instead of the physical. How will this most esteemed group of Spaniards bounce back from their Dutch demolition, and will it be enough to outdo a buoyant Chile side free of pressure?
Squawka's Nic English is expecting the match will live up to its hype:
And that mental note will be so essential as Chile maintain their status as underdogs while La Furia Roja seek to prove last week's routing at the hands of Holland was nothing more than an anomaly.
Del Bosque's side will look to claim the possession they struggled for at times against the Oranje, but Chile will be more than prepared for that eventuality; the quick-shifting wing-backs of their back five can do damage on the break.
Bringing the Group B decider down to the final day, it seems that a draw could once again be the end product between these two, but that doesn't make for any lack in entertainment.
Prediction: Spain 2-2 Chile