Australia were 20-3 up after 30 minutes but the home side stormed back to score 38 unanswered points to the delight of a sell-out crowd in Santa Fe and went on to add more in their biggest win in the Rugby Championship.
Fullback Juan Cruz Mallia and substitute loose forward Joaquin Oviedo both scored two tries and there was one each for Mateo Carreras, Juan Martin Gonzalez, Pablo Matera, Lucio Cinti and captain Julian Montoya on his 100th appearance for the Pumas.
It was a record number of points conceded by Australia, who had only conceded more than 60 points in a test once before when losing to South Africa in 1997.
The Wallabies had edged a 20-19 win over Argentina at a rainy La Plata last weekend for a first victory in this year’s southern hemisphere championship and got off to a good start in the sun in Santa Fe with tries for Carlo Tizzano and Andrew Kellaway in the opening half hour helping them to a 20-3 lead.
But that was as good as it got for the visitors as Argentina, with the jeers from agitated fans ringing in their ears, bounced back immediately to score two tries of their own in the last 10 minutes of the half and reduce Australia’s lead to 20-17 at the break.
Carreras dashed through the middle for the first and Montoya went over after a tap penalty for the second.
They took the lead eight minutes into the second half as Gonzalez went over from a five-metre scrum and never looked back as they piled on the points.
The scoreboard could hardly keep pace as Matera got due reward for his endeavour before Oviedo scored the first of his tries to make it 41-20 in the 65th minute.
Australia replacement Tate McDermott’s try four minutes later briefly offered the visitors hope of getting back into the game as they scored their first points in 30 minutes.
But it proved a temporary blip as Argentina continued to attack with wave after wave of expansive rugby.
Mallia got two tries down the right wing in the space of three minutes, Oviedo took it past the 60-point mark and Cinti rounded off the performance with a try from the last move of the game.
Six of the Pumas' tries were successfully converted by Tomas Albornoz and two by his replacement Santiago Carreras as Argentina posted their best result in the competition, easily bettering the 48-17 win they had over Australia in San Juan two years ago.