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  The Irish were 17-0 down inside the opening 13 minutes in Cardiff and went on to lose heavily 43-20.
  "We just did not get the start that we needed, particularly with a group low on experience," said Schmidt.
  "The confidence got dented a little bit but I was incredibly proud of the way they fought their way back."
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  They went into the match without influential performers Paul O'Connell, Johnny Sexton, Peter O'Mahony, Sean O'Brien and Jared Payne - and got off to a terrible start by conceding a third-minute try.
  A second try and penalty followed before Ireland got themselves on the scoreboard.
  Ireland summoned up a big effort after half-time as Jordi Murphy's try helped cut the margin to only three points before Ian Madigan missed a long-range penalty that would have levelled the game.
  "We had a kick which could have drawn us level and might have allowed us to kick on," Schmidt added.
  "It wasn't to be and really when you try a little too hard at the end you get loose and, with the speed merchants Argentina have, they finished off another couple of tries and that exacerbated things.
  "It reflected the tour de force we have seen demonstrated by the southern hemisphere teams.
  "We were desperate not to be part of what happened in Saturday's matches."
  Ireland skipper Jamie Heaslip: "We are obviously very disappointed to lose in such a big game.
  "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 could not take our opportunities."
  Argentina's Juan Imhoff: "It was a tough game, we worked a lot to get this victory.
  "We will enjoy this, but next week we will have another tough game.
  "We are a really good team in offence, we attack very well, but today we had a defence to make the difference."
summary: Ireland's slow start to their World Cup quarter-final against Argentina proved their downfall, head coach coach Joe Schmidt has admitted.