Messi blew a gilt-edged opportunity to seal victory when he missed a second-half penalty, with the Group D match ending 1-1 after Iceland’s Alfred Finnbogason cancelled out Sergio Aguero’s opening goal.
It was a major embarrassment for the two-time world champions and raises questions about their ability to claim football’s biggest prize for the first time since 1986.
As a cigar-puffing Diego Maradona looked on at Moscow’s Spartak Stadium, Messi also failed to respond to his rival Cristiano Ronaldo’s hat-trick for Portugal against Spain a day earlier.
Messi is yet to win a major international tournament and time is running out with his 31st birthday looming.
But Sampaoli said Argentina would regroup, beginning with their next match against Croatia in Nizhny Novgorod on Thursday, and move on from the Iceland disappointment.
There’s a certain amount of frustration when you come to win a game and don’t get there,” he said. “We were enthusiastic but we played against a structured team.”
He refused to single out Messi for his penalty miss.
“Evaluating Leo’s performance is very difficult because they played almost the whole game in their own half,” he said. “I know he’s committed to helping us get into the next round.”
While the result was not on the scale of that Iceland produced to eliminate England at Euro 2016, it was a major boost for the tiny nation, who retain hopes of advancing from a group that also includes Nigeria and Croatia.