Scotland snatched a 21-19 victory over Argentina in their Test match in Cordoba.
A penalty in the closing stages from Duncan Weir secured victory for Vern Cotter's young team.
However, Argentina spurned a late drop goal attempt as they sought to deny the tourists a morale-boosting success ahead of next Saturday's match against South Africa in Port Elizabeth.
Weir had missed a simple conversion after Henry Pyrgos' try appeared to have set Scotland up for victory, but he regained his composure to land the more difficult penalty soon afterwards. Tommy Seymour was the Scots' other hero as he laid on both their tries.
After struggling to win in the United States and Canada, Scotland knew they had to step up the quality.
But they were always second best at the skilful parts of the game and a try in each half for flanker Javier Ortego Desios and replacement wing Joaquin Tuculet seemed to have put the Pumas on their way before Scotland fought back in the final minutes.
With Scotland making 11 alterations from the side that escaped with a win over Canada, and Argentina switching nine from their narrow loss to Ireland, it was always going to be a slightly disjointed game.
On top of that both coaches had opted for youth with three of the Scotland team making their first starts, a new captain in 23-year-old Grant Gilchrist playing only his seventh Test and two who have made their debuts only on this tour.
There was little to split the teams in the early exchanges. Both sides managed to give the ball away inside the first five minutes with knock-ons that suggested their lack of cohesion, but also made enough inroads with ball in hand to hint at better things to come.
Scotland drew first blood when wing Seymour was put away on a charge down the touchline, brushing off a tackle from opposite number Santiago Cordero and standing strong to offload to full-back Stuart Hogg as the cover came across to hand him an easy score, with Weir converting.
The Pumas were looking the more fluent handling side, however, and a series of clever offloads got them to the Scots' line where they manufactured an overlap for Desios to score their opening try. Nicolas Sanchez missed the conversion but soon added a drop goal to hand his side the initiative, though he missed his attempt to repeat the dose.
Weir also missed a long-range penalty that would have put Scotland ahead and it was the home side who were able to head to the changing room with a slender half-time lead.
Argentina soon increased their lead with two Sanchez penalties, and though Weir's own three-pointer came in-between , mistakes prevented Scotland pulling ahead.
First they made a mess of a scoring chance of their own when they over-elaborated on a four-two overlap, and then they missed a vital tackle in their own 22 to allow Tuculet to wriggle through for a score that seemed to have settled the result.
Scotland gave themselves late hope with a penalty that cut the deficit to six and then Seymour again powered down the wing to hand the try to replacement scrum-half Pyrgos.
Weir was obviously angry with himself when he missed the conversion that would have put his side ahead but he made no mistake with his chance at redemption and was the first to raise his arms in triumph as the final whistle went after Sanchez missed a long-range drop goal attempt.