The Glasgow Warriors star, who had an outstanding RBS 6 Nations, sat that match out but was recalled for the second game and helped Scotland record one of their finest wins of recent times - a 26-14 win.
And Barclay insists they must not make the same mistake this time around.
"Argentina taught us an important lesson about intensity in the first test two years ago," said Barclay.
"Then the second Test was one of the most enjoyable games I've played for Scotland - we played some really great stuff and there was never any question in my mind that we would win.
"But Argentina have a great forward pack, they have backs who will run at us, they are one of the best teams in the world so it will be a big challenge for our pack especially, scrum and lineout and at the contact area as well.
"That is what you want, Argentina is a great place to play and a great place to win."