In a chaotic, helter-skelter game of 42 handling errors and 31 turnovers despite ideal conditions, the Pumas showed their class on Saturday by being ruthless when Italy made mistakes.
Seven different Pumas scored tries, including flyhalf Tomas Albornoz, who added 15 points off the tee.
It tallied into Argentina's biggest win against Italy in their contest's 46-year history. The Pumas had never passed 40 points against Italy in their previous 23 matchups.
The Pumas stretched their winning run against Italy to nine Tests since 2008. Italy haven't won a home game against the Pumas since 1998.
Argentina rebounded from losing the Rugby Championship title decider to South Africa in Mbombela in September with a confidence booster before facing Ireland next Friday.
The Italians endured a sobering night, producing their worst performance of a year in which they beat Scotland and Japan and drew with France.
They were expected to be competitive in the first Test matchup between Argentina and an Argentine coach, Italy's first-year mentor Gonzalo Quesada.
Despite their litany of errors, they stayed in touch with Argentina until an hour in, when they began slipping off tackles more often and couldn't match the firepower off the Pumas bench.
It started poorly for Italy. Star fullback Ange Capuozzo walked off after seven minutes with a head injury after tackling 124-kilogram prop Marco Riccioni.
After 11 minutes, Argentina led 10-0. The Italians flubbed a pass near Argentina's 22 and stopped but Pumas fullback Juan Cruz Mallia didn't. He scooped up the ball and sprinted 75 metres to the try-line.
The Pumas' second try was gifted, too, when a loose ball wasn't controlled and scrumhalf Gonzalo Bertranou grabbed it and touched down.
Italy got a penalty try after Argentina's Juan Martin Gonzalez was yellow-carded for illegally collapsing a maul.
Italy should have had another try before halftime but they didn't protect ruck ball in the Pumas 22, and prop Mirco Spagnolo had a score ruled out. His knees were said to have touched the ground but video showed they didn't.
Tommaso Allan's second penalty at the start of the second half closed Italy to 17-13, and they were still in range when Pumas prop Joel Sclavi broke off a maul and scored.
But when Albornoz raced over for a try in which the buildup included a knock-on, dropped catch and dropped pass, Argentina were 31-13 up and safe.
The Pumas finished with tries for replacements Santiago Cordero, Matias Alemanno and Bautista Delguy, while Italy bagged a try through hooker Giacomo Nicotera but finished with 14 men after No. 8 Lorenzo Cannone was sin-binned for a reckless tackle.
The manner and size of the defeat will embolden Georgia when they visit Italy next weekend.
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