Argentina's forward and captain Lionel Messi celebrates after scoring a goal during a Group F football match between Argentina and Iran at the Mineirao Stadium in Belo Horizonte on June 21. (Pedro Ugarte/AFP/Getty Images)

When Argentina's Lionel Messi curled a sumptuous strike past the opposition goalkeeper deep in stoppage time during a match against Iran on Sunday, his nation heaved a sigh of relief. The Argentines are heavyweights and one of the top contenders to win the World Cup; the Iranians, on the other hand, are relative minnows who were deeply unlucky not to get something out of the game after a dogged, defensive display. Despite the loss, many proud Iranians took to the streets in celebration of their national team's performance.

But in neighboring Iraq, another group also cheered. Or so it seemed: A Twitter account affiliated with ISIS, the extremist militants who have seized a whole section of the country, tweeted the following message below, congratulating Messi on the goal and inviting him to "join the jihadist call."

Why would the militants be so excited about Messi's victory over courageous underdogs? Well, it's a joke.

But there are reasons for animosity: Iran, a Shiite theocratic state, is deeply at odds with ISIS, whose fighters espouse a puritanical form of Sunnism. Tehran has stepped up its support to the embattled government in Bagdhad, currently dominated by Shiite politicos, and is reportedly helping mobilize and train Shiite militias against the ISIS advance.

In its final group match later this week, Iran plays Bosnia, a country that has its own history of outside jihadis offering unwanted support. One wonders what proclamation ISIS will conjure then.

Sunni militants pejoratively refer to Iranians and their allies in Iraq as "Safavids," a gesture to the powerful medieval Shiite dynasty in Iran that expanded Persian borders and battled with the Ottoman empire, then the main champions of Sunni Islam. Messi, who plays for FC Barcelona in Spain, probably has no clue what he's been dragged into.

Correction: While the post suggested the tweet was a joke, it incorrectly represented the Twitter account as being "affiliated" with ISIS. The account @Daash_News monitors ISIS news, often with sarcastic remarks.