After defeat to South Africa last time out, Scotland needed to bounce back and thanks the boot of Greig Laidlaw it did just that.
Sean Maitland scored the only try of a game that lacked a lot of free-flowing play, his score coming after Laidlaw had kicked three penalties from the tee.
While it may not have been Scotland's finest display, Townsend was delighted his side was able to find a way to claim victory.
"I am impressed the team found a way to win," he told BBC Sport. "We were tested today. Argentina kept the ball for a lot of phases and they played well.
"The conditions meant it wasn't going to be a game won off passing the ball wide.
"We didn't have our best first half admittedly, but I felt second half we brought more energy to the game and did enough to win."
Defeat was the third of the month for Argentina, but despite its disappointing European tour, captain Pablo Matera believes the Pumas are in good shape heading into a World Cup year.
"It was a really tough game," he said. "Either of the teams could have won today.
"It is a tough way to finish our season but next year is an important year and I think we are going to take a lot from this game. I am sure it is going to help us become a better team next year.
"I think we are in a good position [approaching the World Cup]. We have had a lot of growth this year and we are improving a lot. Our way of playing is a lot better than last year, and we are going to keep improving and be a stronger team."