Six Nations champions Ireland beat Argentina 17-29 at Estadio Centenario in Resistencia to secure their first ever victory on Argentinean soil.
Ireland scored tries through Chris Henry, Jonny Sexton and Andrew Trimble, Sexton kicking a conversion and two penalties, the latter feat matched by his replacement Ian Madigan.
Manuel Montero scored a memorable try for the under-strength Pumas, Nicolas Sanchez adding a conversion and penalty before Tomas de la Vega crossed for a late consolation try converted by Santiago Gonzalez Iglesias.
Ireland were guilty of trying to play too much rugby in their own half against a spirited Argentina side missing the bulk of their foreign-based players and based largely around the country's second-string Pampas side.
Sexton opened the scoring for the Irish with a 10th minute penalty.
Argentina responded immediately, almost scoring what would have been a fantastic length-of-the-pitch try with a quick tap-and-go from their own line.
Unluckily for the home side, centre Gabriel Ascarate's kick ahead bounced into touch instead of the hands of the two chasing attackers.
Luke Marshall and Darren Cave, the latter wearing the number 13 shirt vacated by now-retired talisman Brian O'Driscoll, both impressed early on against an inexperienced Pumas midfield defence.
And the pressure paid off with Sexton nailing his second penalty, Pumas counterpart Sanchez then pulling one of his own back.
Sanchez turned playmaker shortly afterwards, stepping inside Marshall and offloading to giant winger Montero, who fended off Sexton in a high-class finish that saw him dot down one-handed in the corner, Sanchez converting.
Ireland stormed straight back, Ulster flanker Henry driven over from short range as the visitors took advantage of Pumas No 8 Benjamin Macome, yellow-carded for taking out Trimble in the air.
Just four minutes into the second period, Sexton was on hand to round off a slick midfield wrap-around, showing good strength to ride two tackles to cross for Ireland's second try, but again pushing the conversion wide.
Ireland withstood 10 minutes of heavy Argentinian pressure, Trimble eventually latching on to a floated Sanchez pass to sprint away for a facile intercept try, Sexton converting.
Sanchez saw a penalty effort drift wide as Ireland went close through Cave in the corner with the home side flagging.
Replacement fly-half Ian Madigan hit two penalties to pull the Irish safely clear.
But the Pumas weren't done, De la Vega crossing late for a deserved try, converted by Iglesias.
The two teams meet again next week in Tucuman.
Final Score Argentina 17 (10) Ireland 29 (11)
Tries - Montero, De la Vega,
Con - Sanchez
Tries - Henry, Sexton, Trimble
Pen - Sexton (2), Madigan (2)
Con - Sexton (2)
Referee: Glen Jackson (New Zealand)
Assistant Referees: Mike Fraser (New Zealand), Jaco van Heerden (South Africa)
TMO: Shaun Veldsman (South Africa)
Argentina: 15 Joaquin Tuculet, 14 Santiago Cordero, 13 Jerónimo De la Fuente, 12 Gabriel Ascarate, 11 Manuel Montero, 10 Nicolás Sánchez, 9 Martin Landajo, 8 Benjamin Macome, 7 Tomás De la Vega, 6 Rodrigo Baez, 5 Tomas Lavanini, 4 Manuel Carizza, 3 Ramiro Herrera, 2 Matías Cortese, 1 Lucas Noguera Paz
Replacements: 16 Julian Montoya, 17 Bruno Postiglioni, 18 Nahuel Tetaz Chaparro, 19 Matías Alemanno, 20 Javier Ortega Desio, 21 Tomás Cubelli, 22 Santiago González Iglesias, 23 Lucas González Amorosino
Ireland: 15 Felix Jones, 14 Andrew Trimble, 13 Darren Cave, 12 Luke Marshall, 11 Simon Zebo, 10 Jonathan Sexton, 9 Conor Murray, 8 Jordi Murphy, 7 Chris Henry, 6 Robbie Diack, 5 Paul O'Connell (c), 4 Iain Henderson, 3 Mike Ross, 2 Rory Best, 1 Jack McGrath
Replacements: 16 Damien Varley, 17 Dave Kilcoyne, 18 Rodney Ah You, 19 Devin Toner, 20 Jamie Heaslip, 21 Kieran Marmion, 22 Ian Madigan, 23 Fergus McFadden