Only in the last 20 minutes did the limited Scots find anything resembling an attacking edge, and it resulted in replacement scrum-half Chris Cusiter’s try just after the hour mark.
Scotland plugged away in a tense last few minutes looking for a final score as Argentina were forced to hang on after looking so comfortable for much of a low-quality affair.
Chris Paterson and Dan Parks kicked a penalty apiece for the Scots, with the former adding a conversion, but they made too many errors which the below-par Pumas were glad to punish.
The South Americans’ only try came in the 33rd minute after Gonzalo Longo Elia charged down a Parks kick and collected to go over. Felipe Contepomi converted and added two penalties to give his side a 13-6 half-time lead.
The centre kicked another penalty before Juan Martin Hernandez booted a drop goal and, despite Cusiter’s late salvo, the unbeaten Pumas deserved to advance to their first World Cup semi-final.
Scotand struck the first blow when scrum-half Mike Blair was tackled in the air from the umpteenth up-and-under from Hernandez and Parks knocked over his penalty from halfway.
Contepomi, who had been struggling with flu in midweek, found his range in the 23rd minute, booting over from 40 yards after Nathan Hines’ tackle on Hernandez was deemed high.
With Scotland’s kicking game beginning to flounder, the Pumas were gaining the upper hand and were soon celebrating the first try of the match.
Parks’ clearance was charged down by Longo Elia and the number eight beat Sean Lamont and Ross Ford to the spinning ball to control and ground.
Paterson replied immediately with his first penalty two minutes before the break to make it 13-6 but the Pumas built on their lead with an early second-half penalty by Contepomi.
Parks then missed Scotland’s first penalty miss all tournament and Hernandez added three more points when he dribbled a left-footed drop-goal through the posts.
Unforced errors continued to strangle the life out of Hadden’s side, but introducing the cavalry off the bench just before the hour mark altered things slightly.
Two of them made the breakthrough they were looking for in the 63rd minute. A rampaging run from Craig Smith pierced the Argentina rearguard and the ball was taken on by Sean Lamont down the right.
It eventually found its way to the left flank where Kelly Brown off-loaded for replacement Cusiter to scramble over. Paterson’s conversion clipped the post but went over and it was 19-13.
Fly-half Dan Parks admitted Scotland started playing too late. “We will look back at the tape and think we should have won. But we’ll move on.”
Coach Frank Hadden disagreed, however, and believed the Pumas’ ‘maturity’ was key to their success.
“They had a stranglehold on the game and are very difficult to play against,” he added. “They were a bit more mature in the decision-making around the ball. We didn’t play well enough, but credit to the Argentina defence, they made life very difficult for us. It took us just a little bit too long to get into the game.”
Argentina — Tries: Longo Elia. Cons: F. Contepomi. Pens: F. Contepomi 3. DG’s: J. Fernandez Lobbe. Scotland — Tries: Cusiter. Cons: Paterson. Pens: Parks, Paterson.
Corleto, Borges, M. Contepomi, F. Contepomi, Agulla, Martin Hernandez, Pichot, Roncero, Ledesma, Scelzo, C. Fernandez Lobbe, Albacete, Ostiglia, J. Fernandez Lobbe, Longo Elia.
Senillosa for M. Contepomi (67), Hasan for Scelzo (57), Kairelis for C. Fernandez Lobbe (51), Leguizamon for Ostiglia (55).
R. Lamont, S. Lamont, Webster, Dewey, Paterson, Parks, Blair, Kerr, Ford, E. Murray, Hines, Hamilton, White, Hogg, Taylor.
Southwell for R. Lamont (68), Henderson for Dewey (41), Cusiter for Blair (56), Smith for Kerr (56), S. Lawson for Ford (68), MacLeod for Hamilton (56), Brown for Hogg (56).
J Jutge (France).