Dragons RFC scrum half Gonzalo Bertranou climbed off the bench to score a crucial try as Argentina overturned a 15-point deficit to seal a series-clinching 34-31 win over Scotland in Santiago del Estero.
Duhan van der Merwe and Ewan Ashman each scored two tries as the tourists built up a 28-15 advantage.
But Emiliano Boffelli added to earlier scores by Santiago Carreras, Nahuel Tetaz Chaparro and Bertranou - just five minutes after being introduced from the bench - to give the Pumas a 34-31 win.
Michael Cheika's side had won the first Test before Gregor Townsend's Scots bounced back with victory last weekend.
Congratulations to Gonzalo who will now await news of the Argentina squad for the upcoming Rugby Championship in August and September against Australia, New Zealand and South Africa.