Stand-in Ireland captain Jamie Heaslip has admitted that Ireland gave themselves a mountain to climb by conceding two early tries to Argentina.
The Pumas, who ran out 43-20 winners, went 17 points clear of Ireland within the first 20 minutes of the Rugby World Cup quarter-final.
"We're obviously very disappointed to lose in such a big game," Heaslip, who took over the role of captain following Paul O'Connell's injury, told ITV.
"We didn't help ourselves at the start but we fought back, we came back in it, but we gave ourselves too much (to do) at the start.
"Argentina played a very expansive game, they stretched us and they took their scores when they got them. We got it back to three points and they took their opportunities again to kick on, and we just couldn't take our opportunities."
Ireland once again bow out of the tournament at the quarter-final stage, while Argentina advance to face Australia in the second semi-final on October 25.
