The query has been a common one in locker rooms from La Liga to the Champions League to the World Cup. Having only celebrated his 27th birthday last month, the diminutive forward has already built a compelling case for being the greatest player of all time.
Messi's deadly combination of speed, skill and finishing prowess is unrivaled. For a player who once scored 91 goals in 69 games during a calendar year, the concept of "containment" takes on a new meaning. Defenses must lower the bar when it comes to limiting Messi.
It only seems appropriate, then, that the World Cup final between Argentina and Germany is being billed as "Messi vs. the machine." While the Barcelona star has largely carried his nation's attack en route to Sunday's showcase, the Germans have relied on well-oiled, top-to-bottom consistency.
And that's how they can keep Messi under wraps at the Maracana.
MESSI'S TOUCHES FOR ARGENTINA VS. SWITZERLAND (LEFT) AND NETHERLANDS
Early in this tournament, Messi worked as a loosely defined right winger. Although it was called a 4-3-3, Argentina essentially played a glorified 4-4-2, with Angel di Maria on the left, Messi on the opposite side and Sergio Aguero next to striker Gonzalo Higuain.
But a leg injury to Aguero saw Ezequiel Lavezzi enter the fold as a traditional wide presence, forcing more involvement centrally from Messi in the round of 16 victory over Switzerland. He basically became the second striker underneath Higuain.
Di Maria's thigh injury in the quarterfinals caused further adjustments, with the less-influential Enzo Perez coming on. In the semifinals, Argentina's shootout triumph over the Netherlands saw Messi fall deeper into midfield than he had all tournament.
While Di Maria had made a habit of drifting inside to find the ball in central areas, his absence — along with the Netherlands' stingy tactics — changed Messi's approach. Suddenly, Messi wasn't just being relied on to do his damage in the final third, between the midfield and defensive lines. If he wanted time on the ball, he needed to start sparking attacks in their infancy.
As the Dutch figured out during the scoreless draw, the further Messi is from goal, the better.
AVERAGE POSITIONS FOR ARGENTINA VS. NETHERLANDS (LEFT) AND GERMANY VS. FRANCE
What role Messi (No. 10) will be assigned in the final remains unclear. Aguero is available to play but would be a gamble in the starting 11. Di Maria is more of a long shot, yet not ruled out.
With Messi playing more centrally, the responsibility of containing him will largely fall on German midfielders Bastian Schweinsteiger (No. 7) and Sami Khedira (No. 6). Even though Germany has thrived since Philipp Lahm returned to right back, one must wonder if the captain would be a useful asset as a holding midfielder shadowing Messi.
In the projected duo, Schweinsteiger serves as the deep-lying playmaker while Khedira is a box-to-box presence. As a result, it likely will be Khedira who spends more time tracking Messi — a task the Real Madrid man will be familiar with from many a Clasico clash in La Liga.
In particular, Germany's midfielders must provide support for left back Benedikt Howedes. With Messi still shading to his right in recent matches, the Germans won't want a slower player like Howedes isolated.
Of course, it's not up to just one player — Khedira or Howedes or anyone else — to stifle Messi. His free-roaming nature means pretty much everyone on the German side will be called upon to hold him in check at one point or another. Lahm will take Messi when he floats to the left. Toni Kroos will apply pressure when Messi drops deep. And so on.
That's the nature of this German team, after all. Even a truly special talent can be trumped by elite execution.
Now it's up to Messi to see if he can throw a wrench in the machine.