A Duncan Weir penalty in injury time was enough to give Scotland a battling 21-19 victory over Argentina in a one-off Test match in Cordoba on Friday.
It meant three away wins out of three for the Scots under new coach Vernon Cotter following narrow victories over the United States and Canada.
The close-season tour ends next week end with a game against South Africa in Port Elizabeth.
Stuart Hogg and Javier Ortega Desio traded first-half tries in Cordoba before Nicolas Sanchez’s drop-goal gave the Pumas an 8-7 lead at the break.
The home team then took command in the second half and moved nine points clear with a try from replacement winger Joaquin Tuculet and two penalties from Sanchez.
But, after missing an easy conversion after a try from scrum-half Henry Pyrgos, Weir held his nerve to kick his third successful penalty.
Cotter, who joined Scotland from French side Clermont, made 11 alterations from the side that escaped with a win over Canada.
With 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 had made their debuts only on this tour.
Cotter said the way his side had battled to the end to snatch vicory away from Argentina would stand his team in good stead for the future.
“There is a big difference between losing by a couple of points and winning by a couple of points,” the New Zealander said.
“We will get confidence from this because we came back from a difficult situation. We perhaps didn’t score when we could have scored but we kept at it, we kept building and constructing our play.
“We will keep our feet on the ground, we know next week (against South Africa) is going to be harder.
“There were some every positive things in this display, though, the line out, the scrum, even launching the play off the set phase, we just need to keep the ball a bit more.”
Pumas lock Manuel Carizza said that Argentina had lost their focus late in the second half.
“Maybe we thought we had the match won and thus gave away needless penalties that we had been avoiding for the rest of the match,” he said.