Messi made an unhappy start to the World Cup on Saturday, missing what would have been a winning penalty as Argentina were held to a 1-1 draw by minnows Iceland.
It was a result that has renewed doubts about Argentina's ability to mount a sustained challenge at this World Cup, four years after they reached the final in Brazil.
Another adverse outcome on Thursday and many may even start to consider the unthinkable -- that Argentina could be on their way out at the group stage, mirroring their shock first round exit in 2002.
Legend Diego Maradona called the Iceland result a "disgrace" and warned coach Jorge Sampaoli he would not be able to return to Argentina with similar performances.
Adding to the sense of disappointment, Messi's missed penalty was accompanied by 11 unsuccessful shots, the most in a World Cup game without return by a single player since Italy's Luigi Riva in 1970.
Argentina's players however have been quick to close ranks around the Barcelona superstar.
"We are all with him, he knows that he can count on the support of all of us more than ever," said Argentina striker Paulo Dybala.
"We are here to help him every moment, and of course we will be at his side," Dybala added.
Defender Cristian Ansaldi meanwhile insisted Messi was in good spirits despite the Iceland setback.
"We all know what Messi represents to our team and to our country," Ansaldi said. "Not only is he the best player in the world on the pitch, he is also best player off the field. He's in good shape and that's good for us."
Despite the solitary point against Iceland, Argentina can take solace from a performance which saw them muster 26 shots and have 72 per cent possession against Iceland.
Sampaoli is reportedly considering several changes for the game, including drafting in young forward Cristian Pavon for Angel Di Maria for more creativity up front.
Similarly in midfield, Paris Saint-Germain's Giovani Lo Celso could start as Argentina seek more attacking options, possibly at the expense of Lucas Biglia.
Their jobs would be to supply Messi and goalscorer against Iceland Sergio Aguero with the kind of service on which they would thrive in a potential 3-3-3-1 formation.
Croatia may have secured a vital three points in their 2-0 win against Nigeria in their opening game, but their mood can hardly be described as euphoric.
They came into the tournament under a cloud, with captain Luka Modric charged with perjury in a corruption scandal which has rocked Croatian football.
And striker Nikola Kalinic has left Russia due to a back injury, says coach Zlatko Dalic, but amid reports he refused to come on as a substitute after being left out of the starting line-up.
Off-field problems for now though have not affected them and they are expected to field an unchanged team, which also includes Messi's Barcelona teammate Ivan Rakitic.
The teams have met only once before in the World Cup, in 1998, when Argentina won 1-0 and were the only team that year to prevent Golden Boot winner Davor Suker from scoring.
One other possible omen for Thursday; when Riva racked up his unwanted record in 1970, the Italian legend promptly scored two goals in his next match.
Argentina will be hoping for the same from Messi.