Tucuman - Ireland have toughed out a 23-17 win over Argentina in their second Test and earned its first series triumph in Argentina on Saturday.
A week after winning in Argentina for the first time, 29-17 in Resistencia, the vastly more experienced Six Nations champion conceded the lead to the mainly home-based Pumas in the 25th minute and didn't get it back for good until the 50th with the first of its two tries.
The Argentines played most of the match inside their half, but their swarming defence kept turning over Irish possession and launching dangerous breakouts.
"That was an exercise in frustration," Ireland coach Joe Schmidt said.
"It was difficult to get continuity going. It was a disappointing performance by our standards."
With Irish wing Andrew Trimble in the sin-bin for a too-early tackle on counterpart Lucas Gonzalez Amorosino, Pumas scrumhalf Martin Landajo darted out of his 22.
The counterattack up the right touch appeared to die when Gonzalez Amorosino was enveloped five metres out, but the ball was spread left and fullback Joaquin Tuculet wrong-footed defenders to score.
Nicolas Sanchez's conversion gave Argentina a 10-9 lead into the break following three Jonathan Sexton penalties.
Ireland could blame only itself for trailing at halftime: Left wing Simon Zebo stepped into touch with a free run at the tryline, Jamie Heaslip passed forward to Chris Henry five metres out, and fullback Rob Kearney's fine break and run into the 22 was ruined by Sexton chipping straight to the Argentines.
Ireland continued to dominate in the second half but struggled to score.
Tuculet made a try-saving tackle on Trimble before scrumhalf Eoin Reddan drew the defence off a ruck and passed inside for Zebo to slice through to the line for 16-10.
Midfielder Darren Cave was penalized for a double movement on the tryline, then flyhalf Sexton went off after a clash of heads and was replaced by Ian Madigan.
Madigan's first try for Ireland, seven minutes from time, put the result out of Argentina's reach, though the Pumas scored late when Gonzalez Amorosino stepped past Madigan and crossed to even the try count.
Ireland: 23 - Tries: Simon Zebo, Ian Madigan; Conversions: Jonathan Sexton, Madigan; Penalties: Sexton (3)
Argentina: 17 - Tries: Joaquin Tuculet, Lucas Gonzalez Amorosino; Conversions: Nicolas Sanchez, Santiago Gonzalez Iglesias; Penalty: Sanchez