Ireland flanker Keith Gleeson believes his side paid the penalty for their indiscipline during Saturday's defeat by Argentina in Santa Fe.
A last-gasp drop goal by Felipe Contepomi gave Argentina a 22-20 win against Eddie O'Sullivan's side, and Gleeson, 29, was left to rue a string of indiscretions which handed control of the match to the hosts.
He said: "We are disappointed.
"We went into the break at half-time doing well but in the second half we just gave away too many penalties and Contepomi just punished us."
Of Leinster fly-half Contepomi, who scored 17 points, Gleeson added: "Every time we gave away one penalty, he (Contepomi) was there to score it and that's they way they took away our lead."
"I insist on being disappointed because we played quite well up to the last stages of the second half."
Gleeson compared the game's intensity with the 2003 World Cup Group match game Ireland won 16-15 against the South Americans.
"It was very similar to the match we played in Adelaide in 2003, as that game came down in the last 10, 15 minutes and the score went both ways.
"I think it was a great game to watch from the spectators' point of view here in Santa Fe. It was intense and both teams had chances to win it."
Ireland will have a chance for revenge next Saturday at Jose Amalfitani in Buenos Aires.
Coach Eddie O'Sullivan agreed that a lack of discipline was the main reason for the defeat, but Gleeson also highlighted other problems which need to be addressed before the rematch.
"There are a lot of areas that we must improve ahead of the second Test," he commented.
"Defensively we played quite well, but perhaps attacking-wise, building better platforms and controlling the ball a bit better are some points to work on for next Saturday.
"And certainly discipline is one area - we know we need to stop giving away so many penalties."
O'Sullivan has already promised there will be quite a few changes for next weekend's encounter.
Paddy Wallace will not be present due to a knee injury and O'Sullivan is expected to call-up Jeremy Staunton, who is in England with the Ireland A team, playing in the Churchill Cup.
O'Sullivan is naming his starting XV on Tuesday and Alan Quinlan, Shane Jennings and Stephen Ferris are likely to form a new back row.
England flanker James Haskell insists he will be pushing as hard as possible to be back from a toe injury in time to make his case for a spot in Eddie Jones' side looking to defend their RBS 6 Nations title next year.