Argentina captain Agustin Pichot bemoaned his team's lack of control in their narrow defeat to Ireland in Adelaide.
Pichot was unable to get his backs going against Ireland
The Pumas needed to win to have any chance of going through to the knock-out stages, but were edged out by one point, 16-15.
Argentina are now returning home after winning only two of their pool matches.
"They didn't do anything special," Pichot said of Ireland. "We just didn't do things so well when we should have done when it was crucial.
"We lost composure in the final 15 minutes and were never in control in the critical moments."
Argentina took an early lead but trailed by a point at the break.
They nosed ahead again after Ignacio Corleto landed a huge drop goal midway through the second half.
But they were unable to hold on to their slender advantage when Ireland threw everything at them in the closing stages.
Argentina winger Diego Albanese was blunt in his assessment.
"They took their opportunities and we didn't," he said. "We made a
big effort today and they scored just with one of our mistakes."