A last-gasp Felipe Contepomi drop goal gave Argentina 22-20 victory against Ireland in Santa Fe on Saturday.
Contepomi was the man of the match even though Eddie O'Sullivan's side managed to control the Pumas captain in a first half which belied Ireland's inexperience at full-back.
Simon Best, in his first match as captain, did not disappoint with an outstanding performance.
Full-back Gavin Duffy and wing Brian Carney provided a telling influence in the early part of the game, Carney's movement surprising the hosts as the former rugby league player constantly probed Argentina's defence.
And it was Ireland who broke the deadlock with a Paddy Wallace penalty after six minutes.
A minute later Carney had his reward when he recovered the ball after a misplaced pass by Contepomi and claimed his first try for Ireland on his international debut.
Wallace slotted the conversion to put the visitors into a 10-0 lead.
Contepomi's penalty then reduced the deficit and after he and Wallace missed further kicks at goal, the Argentinian converted just before the break.
Ireland made a nervous start to the second half before Contepomi reduced the deficit to a single point.
Duffy's great kick then gave Ireland great field position and a fantastic 30-yard rolling maul eventually saw the visitors awarded a penalty try. Wallace's conversion put them 17-9 ahead.
However, Argentina hit back through a Contepomi penalty before Hernan Senillosa went over for a try. Contepomi's conversion put the hosts ahead for the first time in the match.
Although Duffy's penalty put Ireland ahead again with three minutes to go, Contepomi's last-gasp drop goal saw Argentina take the lead.
Victory was assured for the hosts when wing Geordan Murphy failed with an attempt at a drop goal.
Pens: Contepomi 4
Drop Goal: Contepomi
Tries: Carney, Penalty
Cons: Wallace 2
Pens: Wallace, Duffy
Argentina: 15 Bernardo Stortoni, 14 Tomás De Vedia, 13 Miguel Avramovic, 12 Hernán Senillosa, 11 Francisco Leonelli, 10 Felipe Contepomi (captain), 9 Nicolás Vergallo, 8 Juan Manuel Leguizamón, 7 Juan Fernández Lobbe, 6 Martín Durand, 5 Esteban Lozada, 4 Pablo Bouza, 3 Santiago González Bonorino, 2 Alberto Vernet Basualdo, 1 Marcos Ayerza
Replacements: 16 Matías Cortese, 17 Pablo Cardinalli, 18 James Stuart, 19 Genaro Fessia, 20 Lucio López Fleming, 21 Juan Fernández Miranda, 22 Horacio Agulla
Ireland: 15 Gavin Duffy, 14 Brian Carney, 13 Andrew Trimble, 12 Kieran Lewis, 11 Tommie Bowe, 10 Paddy Wallace, 9 Isaac Boss, 8 Jamie Heaslip, 7 Keith Gleeson, 6 Neil Best, 5 Malcolm O'Kelly, 4 Trevor Hogan, 3 Simon Best (captain), 2 Jerry Flannery, 1 Bryan Young.
Replacements: 16 Bernard Jackman, 17 Tony Buckley, 18 Mick O'Driscoll, 19 Stephen Ferris, 20 Tomas O'Leary, 21 Geordan Murphy, 22 Barry Murphy.
Referee: Lyndon Bray (New Zealand)
Touch judges: Kelvin Deaker (New Zealand), Phillip Bosch (South Africa)
Television match official: Shaun Veldsman (South Africa)