By Gareth RobertsBBC Sport Wales at the Millennium Stadium
Wales (9) 12
Pens: Halfpenny 4
Argentina (6) 26
Tries : Imhoff, Camacho
Cons: Sanchez 2
Pens: Contepomi, Sanchez
Drop-Goal: Sanchez 2
Argentina consigned Wales to a telling defeat in Cardiff where the Six Nations holders have not won an opening autumn Test since 2000.
The hosts were 9-6 ahead at the break through three Leigh Halfpenny penalties to Felipe Contepomi's penalty and a Gonzalo Sanchez drop-goal.
But second-half tries from Puma wings Juan Imhoff and Gonzalo Camacho and Sanchez's kicking ensured them victory.
Defeat left Wales interim coach Rob Howley with one win from five starts.
With Tests against Samoa, New Zealand and Australia to come in the next three weeks, the reverse also dented Welsh hopes of a favourable 2015 World Cup draw when it is made in December.
The Pumas displayed their customary muscle and effort up front as well as the defensive qualities that have made them such respected opponents on the world stage.
Howley hugely disappointed following Wales' loss to Argentina
The opening exchanges were brutal and uncompromising, so much so that rival centres Felipe Contepomi and Jamie Roberts had each departed well before the break.
Argentine veteran Contepomi's reward for bringing down high-steppping George North during Wales' first attack was to come off worse in the ruck that followed.
His Test return had lasted only 14 minutes while Roberts paid the price for going in high on Gonzalo Tiesi and collapsing in a heap after his head clashed with the back of Tiesi's.
James Hook took over from Roberts and Wales were further weakened before the break as lock Alun Wyn Jones also departed with less than a minute left with
suspected shoulder damage
and was replaced by Scarlets' number eight Rob McCusker.
The rival medical teams had done some sterling work in that opening period, matched by the efforts of both sides in terms of commitment to the cause.
Official match stats
Scrums won (lost)
Line-outs won (lost)
Tackles made (missed)
(provided by Opta)
But there was little in the way of creativity.
Wales largely concentrated on stretching the ball wide, often around half-way, to little effect while Argentina teased the home defence with some clever kicks.
Wales full-back Halfpenny was the opening period's outstanding performer, dealing with the dangers posed by the kicking of opposite number Juan Martin Hernandez and fly-half Nicolas Sanchez.
The Cardiff Blue also came out on top in the goal-kicking duel, his three penalties to Contepomi's opener and Sanchez's 10th-minute drop goal.
In the absence of Adam Jones, his fellow Osprey Aaron Jarvis performed admirably in the scrums on his Test debut.
Neither side were able to take their first-half try-scoring chances with the visitors particularly unfortunate when Tiesi stumbled and fumbled in attempting to gather off the floor five metres from the line.
Sanchez missed two penalty shots within five minutes of the restart - the first rebounding off an upright and the second falling short after he slipped in the run-up.
But Halfpenny kicked his fourth shot to increase Wales' lead to 12-6 against the run of play.
Argentina coach Santiago Phelan gives his reactions to beating Wales
Sanchez made amends with his second drop-goal to leave the contest on a knife edge.
When Imhoff rounded Halfpenny for the game's opening try in the 55th minute after good work by number eight Leonardo Senatore, the visitors had at last earned a reward for more than holding their own.
As Sanchez kicked the conversion, Mike Phillips replaced Tavis Knoyle at scrum-half for Wales.
But the Pumas were soon back on the attack and after more clever support play, Camacho's outstretched arm beat Halfpenny's despairing tackle at the corner.
Sanchez's conversion from the touchline put his side into a 23-12 lead with the last quarter between Wales and defeat.
Wales' autumn Test schedule
lost 12-26 v Argentina, Millennium Stadium
v Samoa, Millennium Stadium, 1930
v New Zealand, Millennium Stadium, 1715
v Australia, Millennium Stadium, 1430
The Bordeaux-Begles fly-half added another penalty with eight minutes remaining as Argentina profited from their dominance up front that had grown throughout the second period.
At the final whistle Wales, who had made no line-breaks and worked themselves into the visitors' 22 only twice, departed to the boos of their fans.
16-Richard Hibbard (60 for Rees), 17-Ryan Bevington (68 for Jenkins), 18-Paul James (64 for Jarvis), 19-Rob McCusker (39, for AW Jones), 20-Justin Tipuric (70 for Warburton), 21-Mike Phillips (56 for Knoyle), 22-James Hook (24 for Roberts).
Unused: 23-Liam Williams.
: 15-Juan Martin Hernandez, 14-Gonzalo Camacho, 13-Gonzalo Tiesi, 12-Felipe Contepomi, 11-Juan Imhoff, 10-Nicolas Sanchez, 9-Martin Landajo; 1-Marcos Ayerza, 2-Eusebio Guinazu, 3-Juan Figallo, 4-Manuel Carizza,5-Julio Farias Cabello, 6-Leonardo Senatore, 7-Juan Manuel Leguizamon, 8-Juan Martin Fernandez Lobbe (capt).
16-Agustin Creevy (48 for Guinazu), 17-Bruno Postiglioni (78 for Ayerza), 18-Juan Gomez (66 for Figallo), 19-Tomas Vallejos Cinalli (64 for Cabello), 20-Tomas Leonardi (56 for Senatore), 21-Nicolas Vergallo (66 for Landjo), 22-Horacio Agulla (45 for Hernandez), 23-Joaquin Tuculet (14 for Contepomi).
: Romain Poite (France)
: George Clancy & Dudley Phillips (both Ireland)
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