Vicente del Bosque's men arrived in Brazil as one of the pre-tournament favourites having triumphed in South Africa four years ago, as well as retained their UEFA European Championship title in 2012.
However, Spain's World Cup defence began in a disastrous fashion as Louis van Gaal's side stormed to a shock 5-1 Group B victory in Salvador on Friday.
Xabi Alonso's 27th-minute penalty had appeared to put Spain in a strong position, but Robin van Persie's superb headed equaliser shortly before the break triggered a second-half demolition from the Dutch.
Several Spain stars came in for heavy criticism following the crushing defeat, none more so than Iker Casillas, with some calling for the Real Madrid goalkeeper to be dropped from the starting XI.
Del Bosque may retain faith in his captain, however, as David de Gea is struggling for fitness due to a muscle injury, leaving Pepe Reina as the only alternative.
Central defensive pair Sergio Ramos and Gerard Pique as well as Brazil-born striker Diego Costa also faced scrutiny for their performances, but it remains to be seen if Del Bosque will change his line-up or hand an opportunity to the side that failed so spectacularly last week.
Regardless of who gets the nod at the Maracana in Rio de Janeiro on Wednesday, the result will offer some indication as to whether Spain can mount a challenge to return to the iconic stadium for the final on July 13.
It is the second time in as many World Cups that the teams have faced off, Spain triumphing 2-1 in 2010, although both sides still progressed from Group H.
A repeat victory could re-invigorate Spain - who lost their opener in South Africa before going all the way - and forward Juan Mata believes a strong team bond can help them overcome the poor start.
"We have strong faith in our football, in our ideas and we really believe we can overcome the situation," he said. "This group is like a family since I arrived here.
"I think it's vital this kind of friendship between all of us, this familiar feelings which have made the Spain national team into a successful team."
Chile started their campaign with a 3-1 victory over Australia, but that scoreline somewhat belied the difficulty that Jorge Sampaoli's side faced in Cuiaba.
The South Americans were fluent in attack, with Barcelona forward Alexis Sanchez particularly lively, yet goalkeeper Claudio Bravo was required to make a series of saves to deny Australia at least a draw.
Chile have failed to beat Spain in 10 meetings between the teams and even a point could prove crucial in their bid to qualify for the knockout stages.
However, midfielder Arturo Vidal - who managed 60 minutes against Australia as he continues to recover from knee surgery and has declared himself fit to play Spain - insists Chile are only interested in a maximum haul.
"We're going to push forward looking for the three points," he said. "We have our style and we'll keep to it, we'll keep working in the same way and we're not going to change that."
